Recently, the U.S. Department of Agriculture and Health and Human Services issued their new preliminary guidelines for improving the nation’s diet. The major recommendations haven’t changed since the last ones issued five years ago, and include limiting sugar, saturated fats, and salt. Many people find it somewhat easy to cut back on sugar and saturated fats if they try, but reducing sodium intake has remained a problem for even people who try hard to eat better.
It turns out that some people have more trouble than others, and it’s not just a question of willpower. Our genetics influence some of the difference in the levels of salt we like to eat.
Where does the salt in our diet come from?
Americans consume 3,400 milligrams of salt a day on average. That’s more than double the 1,500 milligrams recommended by the new USDA/HHS guidelines and other groups like the American Heart Association and the Institute of Medicine.
Salt (otherwise known as Sodium Chloride), occurs naturally in many foods, but we also add it to our diets directly. Here’s a pie chart which shows where the salt comes from in the average American’s diet:
Image from the Risk Factor Monitoring and Methods Branch Website, part of the Applied Research Program of the National Cancer Institute. http://riskfactor.cancer.gov/diet/foodsources/sodium/. Updated January, 2010. Accessed June 18th, 2010.
In general, most people could benefit by reducing the sodium intake in their diets. But some people find this much harder than others – the question is: why?
Are We Hardwired to Prefer Salt?
By and large, most people prefer saltier versions of foods. How each of us perceives the “saltiness” of a given amount of salt, though, varies widely.
Studies have found that this variation could stem from innate differences in how our tastes function. One of the best-studied markers of how tastes vary is the perceived bitterness of propylthiouracil (PROP). Researchers call people with high sensitivity to PROP “supertasters,” as they are more sensitive to small changes in a number of different tastes. Supertasters are also more likely to eat more salt in their diets. People who are more sensitive to PROP, finding even small amounts bitter, are more sensitive to changes in saltiness, and need higher levels of salt to make bitter foods taste more palatable. PROP sensitivity, as it turns out, is strongly genetic, which would mean we have little control over how bitter or salty foods taste.
But others have suggested that cultural, behavioral or otherwise non-genetic factors are to blame for a person’s relative sensitivity and addicted-ness to salt. The idea is that a taste for salt could be explained by how much salt was eaten as a child or emotional attachments to salty foods. By eating more salt during development, people can influence how they perceive foods later in life.
As the research continues to pile up, though, it seems more and more likely that genetics play a large role in our preference for salt. A study just published in Physiology and Behavior analyzed the PROP sensitivity argument using 87 people. They found, like previous research that some preferred saltiness more than others and needed that salty flavor to make bitter foods taste better. The more sensitive a person was to PROP, the more salt they preferred and ate in their diets. More importantly, these supertasters which preferred salt weren’t adding it to their foods, they were simply eating more in their diets. This means that they might not realize how much salt they are consuming overall, since they aren’t pouring the salt on at the table, so they may believe they’re not eating as much salt as they really are.
Doomed By Our Genes?
The bad news is that our desire for salt may be largely genetic. The good news, though, is that this doesn’t mean you can’t eat healthier and reduce your salt intake. The reason behind the pension for salt in some people is that is helps alter bitter tastes. So, if you avoid bitter tasting foods, you can help avoid the desire for extra salt. Take a look at the chart describing salty foods, and think about what you eat of it. Anything you can do without will help cut your salt intake. Do your best to keep an eye on the amount of sodium you eat, and if you do, you’ll find that you can cut back in little ways that add up without sacrificing the flavor of foods.
Citations Chang WI, Chung JW, Kim YK, Chung SC, & Kho HS (2006). The relationship between phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) taster status and taste thresholds for sucrose and quinine. Archives of oral biology, 51 (5), 427-32 PMID: 16297856
Hayes JE, Sullivan BS, & Duffy VB (2010). Explaining variability in sodium intake through oral sensory phenotype, salt sensation and liking. Physiology & behavior, 100 (4), 369-80 PMID: 20380843
Organic food sales have increased exponentially over the past decade, largely due to consumer perceptions of improved nutritional quality and taste. However, as I’ve explained before, there is scant scientific evidence that growing food organically improves its quality on either front. Since people have a wide array of intellectual biases, some scientists have decided to ask more balanced judges to weigh in on the issue: birds.
It turns out birds aren’t bird brains when it comes to what they eat. A number of species of birds have been shown to choose foods that contain higher levels of healthy things like protein and antioxidants and lower levels of not-so-healthy things like heavy metals and pesticides. Since they’re such finicky eaters, scientists figured to let them choose between conventionally and organically grown food, and see which they deemed better for them. The vote was unanimous: birds prefer non-organic.
Birds Think Conventional Food Is Better
Researchers from Newcastle University purchased Alchemy variety wheat from a number of organic and conventional producers in Europe. They then ground the seed into 2mm or smaller sizes so that there was no textural difference between the two types. In their first experiment, they provided caged canaries with both types of wheat in identical bowls, and recorded how many seeds of each type they ate in 20 minutes. 66% of the time, they picked the non-organic variety – and they picked it more often as time went on, suggesting that those that tried both decided the conventional was better and stopped choosing the organic.
But maybe, the scientists thought, that since canaries are domesticated, it’s possible their food preferences are skewed by what’s provided in their normal, canary feed. Instead, they decided, they wanted to see what wild birds thought of organic and conventional wheat varieties.
They placed each variety in a bird feeders and put them in different gardens throughout northeast England. They measured the weight of food taken from each tube every two days for six weeks. Since wheat isn’t commonly used in commercial food for garden birds, it’s much less likely that they’d have a preference for either type based on previous encounters. To make sure that their own biases didn’t get involved, they coded the bags of wheat and didn’t tell the people who filled the feeders which was which, so they had no idea which feeder contained which type until after the experiment was finished. They chose a few different farms for each type, to make sure that it wasn’t just the effect of one farm’s practices. And just in case position mattered, they swapped the positions of the feeders on the farms, too, halfway through the experiment.
The garden birds, like the canaries, preferred the non-organic food. At 39 of the 45 gardens tested, conventional food eaten outweighed organic food eaten. On average, conventionally grown wheat accounted for ~60% of what the birds ate. And again, the scientists found that as the experiment went on, the birds ate less and less organic wheat.
Why Did The Birds Prefer Conventional Wheat?
The big question, of course, is why did the birds prefer the non-organic varieties? The researchers made sure that texture, size, and position weren’t factors. So what about the conventional wheat was so appealing?
To try and get to the bottom of that question, the scientists tested the different varieties of wheat. They tested their physical properties (weight per thousand seeds, hardness), nutritional levels (moisture, protein, fat, carbohydrate, energy, amino acids), and levels of potential negative qualities (toxin burden, microbes, oxalic acid, and pesticide residues). Levels of moisture, fat, carbohydrate, pesticide residues, cadmium, lead, microbial contamination (Escherichia coli, Salmonella spp., Enterobacteriaceae), oxalic acid, hardness and amino acid content were not significantly different between samples.
They did find one thing that was different, though: levels of protein. The conventional wheat they gave the canaries was 26% higher in protein than the organic, and the wheat they gave the garden birds was 6-26% higher (depending on which farm the conventional or organic wheat came from).
Could protein explain the difference in preference? Well, they decided to test that, too. They grew new samples of wheat under four different levels of fertilizer, yielding four types of wheat that were identical in every way except how much protein they contained. They then took the lowest protein variety and the highest protein variety (a difference of 14% between them) and asked canaries for their opinion. The bird’s choice? The higher protein food.
Ecologically, it makes perfect sense. Protein is an essential nutrient in the diet of all birds and mammals and is often limiting – especially for species that eat grains, which aren’t high in protein to begin with. Studies have found that birds and mammals, particularly if stressed, pick higher protein options. So when the birds in this study were presented with, as far as the birds (and the experimenters!) could tell are two equal foods except that one has more protein, why wouldn’t they choose the higher protein option?
So What Does This Mean For Non-Birds?
While this study is fascinating, and may speak to potential ecological implications of organic farming, it doesn’t say much about whether we should buy organic food or not. Just because the birds chose the conventionally grown wheat doesn’t mean we should, too.
The study found a clear nutritional distinction between the wheat types they used. In a grocery store, things get much more complicated. What would have happened if the conventional wheat had higher protein levels but also had higher pesticides? Would the birds have weighed the risk and reward? It’s anyone’s guess. Also, studies have gone back and forth about whether there are or aren’t differences in nutrition between organic and conventional foods. Even if we were to say we should eat whichever has higher X or lower Y, the jury is still out on organic v. conventional in that respect, too. Furthermore, it’s hard to compare bird nutrition to human nutrition, even though birds tend to prefer foods that are healthy for us, too.
Of course, we can learn a lesson from our feathered friends – they consistently choose the healthiest food option available. How many of us can say the same?
Reference: McKenzie, A., & Whittingham, M. (2010). Birds select conventional over organic wheat when given free choice Journal of the Science of Food and Agriculture DOI: 10.1002/jsfa.4025
ost of us already know that we should be eating fiber – according to the Institute of Medicine, adults should be eating 20-35 grams of it per day. But why? What’s so important about fiber anyway? What does it do for us physiologically? And does it matter what kind of fiber we eat?
I can hear some of you now – wait, there’s more than one kind of fiber? Yes, there is, though you won’t see it detailed on any nutritional label. Most of the time, we’re told to simply focus on total fiber , no matter where it comes from. While getting enough total fiber is key, getting enough of each kind of fiber may be just as important in having a healthy, happy digestive system.
What is Fiber? And what does it do?
Peas, an excellent source of fiber – thanks to Sami Taipale flickr
Fiber is similar to starches and sugars in that it’s mostly made of carbohydrates . The difference is that fiber refers to the carbohydrates that your body can’t digest, while starches and sugars are carbohydrates that humans easily digest. Why would we want to eat something our bodies don’t digest? As it turns out, even though we can’t digest it, fiber helps us digest other things and keeps our digestive system running smoothly. Of course, the kind of fiber matters.
There are two main categories of fiber: soluble and insoluble. Soluble fiber dissolves in water, while insoluble fiber, as the name suggests, doesn’t. The average American fiber intake contains 75% insoluble fiber and 25% soluble fiber, each having its own special physiological impacts on digestion.
Insoluble fiber, like the fiber in whole wheat foods, bran, nuts, and seeds, mostly helps by simply being there. It’s what forms the mass that moves through your bowels, and while that might sound a little gross, it’s key to preventing conditions like diarrhea and constipation. Because it stays in a solid form, it helps compact the forming stool, which allows it to move more easily through the intestines. Some health professionals also believe that insoluble fiber acts like a sponge or scrub brush, cleaning the digestive tract as it goes along by gently scraping the walls and snowballing with stray particles so they are removed from the body.
Soluble fiber, found in fruits, vegetable and flax seed, acts differently because it becomes gel-like in water, actually incorporating with liquids. Soluble fiber helps hydrate stool, allowing it to slip though the intestines smoothly, a key in preventing digestive disorders. But soluble fiber does so much more – often called “viscous fiber“, soluble fiber makes your digestive contents into a thick slurry, which slows down your digestive system, slowing the process of absorption in the small intestine.
The effect of this is that you feel fuller, longer, because of slower, steadier increases in blood glucose levels, and your body requires less food to attain the same absorption of energy and nutrients. One study found that adding one kind of soluble fiber to their subject’s diets reduced the their food intake by 11%!
But soluble fiber also helps regulate the levels of glucose in our blood more directly. Soluble fiber is often fermented during our digestive processes, producing compounds called short-chain fatty acids and gasses (FYI, this is where increases in flatulence can come from when eating beans – legumes are high in soluble fiber and fructo-oligo-saccharides).
Short-chain fatty acids have a number of physiological roles. These small fat molecules have been shown to directly influence insulin release from the pancreas and glycogen breakdown in the liver, leading to stable and healthy glucose levels. Short-chain fatty acids also influence the liver’s production of cholesterol. The effect of this is that increased fiber consumption lowers the circulating bad cholesterol in the blood. They’ve been found to promote the production of immune cells and antibodies, potentially boosting immune function. Furthermore, these little acids help regulate the pH (acidity) of the intestines and the colon, keeping it in the right range to promote nutrient absorption and discourage microbes from producing toxins and carcinogenic substances.
A good video review of this information can be found here:
Fiber and Disease
Mega Burgers, not so hot on fiber – credit, marshall astor
The old adage “an apple a day keeps the doctor away” may be more true than we thought. Apples are great sources of fiber, and both soluble and insoluble fibers help reduce the risk of a variety of diseases. One of the most well understood is fiber’s connection to diabetes. Because fiber slows down your digestive system, glucose enters your bloodstream at slower, more stable rate, and this helps with managing Type 1 diabetes. But fiber can help prevent Type 2 diabetes, too.
Type 2 diabetes can be induced by our diets when our bodies are exposed to high blood glucose levels for a long period of time. This can happen because of consistent over-intake of sugars and carbohydrates, but it can also occur because our bodies are unable to produce enough insulin to lower rising blood sugar levels, or we become desensitized to insulin activity. By creating a slow, steady stream of glucose uptake, fiber helps our bodies avoid the sudden spikes glucose and insulin that, over time, can lead to Type 2 diabetes.
Studies have shown that diets high in fiber reduce the risk of Type 2 diabetes significantly. For example, a meta-analysis of several large studies (totaling to over 700,000 people) found that eating an additional 2 servings of whole grains a day decreased the risk of Type 2 diabetes by 21%. Both soluble and insoluble fiber intake are correlated with reduced diabetes risk, though how the insoluble fiber is involved is less understood.
Fiber is also strongly linked to reducing risk of heart disease. This is likely due to its positive influence on blood cholesterol levels. A number of large, long-term studies have found that people with high-fiber diets have up to a 40% lower risk of coronary heart disease.
Furthermore, a meta-analysis of seven large studies found that the risk of developing cardiovascular disease was 21% lower in people who ate 2.5 or more servings of whole grain foods a day compared with those who ate much less. Mostly, these studies suggest that soluble fiber is the key player in preventing cardiovascular problems. Because of the extensive, strong correlation between soluble fiber intake and lowered risk, soluble fiber is one of the very few things that the FDA officially recognizes as reducing the risk of heart disease.
Furthermore, a recent study has found that increasing soluble fiber intake, but not insoluble fiber intake, actually helps boost our immune systems. Mice were fed low-fat diets that either contained regular amounts of soluble or insoluble fiber for six weeks before being subjected to an agent that mimics a bacterial infection. When the two groups were compared, the soluble-fiber eating mice were only half as sick as their insoluble-eating counterparts, and they recovered 50% sooner. What made the soluble fiber so much better for the mice?
Scientists discovered that the soluble fiber-eating mice were producing higher levels of anti-inflammatory compounds, perhaps due to short-chain fatty acids. Immune cells in our bodies have to deal with both invaders like infections and self-caused problems like inflammation. The researchers believe that by reducing the inflammation response, ingesting soluble fiber altered the mice’s immune cells, making them switch from problematic inflammatory cells to anti-inflammatory cells that can deal with other problems, like the faked infection. While this research is preliminary, it’s impressive that the mice immune systems were altered by manageable amounts of fiber that could easily be eaten by people.
The one thing fiber intake doesn’t help much with, though, is the one disease it’s most often touted as a way of preventing: colon cancer. The truth is that the connection between dietary fiber and reduced risk of developing colon cancer is weak at best. While some smaller studies have linked high-fiber diets to lowered risk of colon cancer, larger ones, like a 16-year Harvard study of more than 80,000 nurses, have found no connection.
Take Home Message: EAT MORE FIBER!
The scientific evidence is unmistakable – fiber is vital for a healthy digestive system. More often than not, you’ll be told to simply eat more fiber, but from the evidence I’ve seen, you should be particularly eating more soluble fiber. And that isn’t the kind of fiber normally touted – often, you hear people push for whole grains, which are good sources of insoluble fiber, even though it’s soluble fiber that is much more strongly linked to fiber’s various health benefits. There’s another problem, too – according to nutrition labels, fiber is fiber. There is no distinction between soluble and insoluble fiber in packaged foods. Instead, you have to be your own nutrition expert, and know which fiber-filled foods are naturally high in soluble fiber. Here are a few good ones:
Foodstuff
Serving Size
Total Fiber (g)
Soluble Fiber
Insoluble Fiber (g)
Grapefruit
1/2 fruit
1.3
0.9
0.4
Squash, summer
1/2 cup
2.3
1.1
1.2
Zucchini
1/2 cup
2.5
1.1
1.4
Brown rice
1/2 cup
1.3
1.3
0
Rolled Oats
3/4 cup
3
1.3
1.7
Orange
1 medium
2
1.3
0.7
Plums
2 medium
2.3
1.3
1
Broccoli
1 stalk
2.7
1.3
1.4
Carrots
1 large
2.9
1.3
1.6
Tangerine
1 medium
1.6
1.4
0.4
Peas
1/2 cup
5.2
2
3.2
Pinto beans
1/2 cup
3
2.2
0.7
Potatoes
1 small
3.8
2.2
1.6
Apple
1 small
3.9
2.3
1.6
Psyllium husk
10g
8
7.1
0.9
Of course, no matter what you should probably be eating more fiber. Studies have found that Americans eat 50% or less than the recommended intake every day! So while soluble fiber may be the best option, any fiber is a start!
What are the downsides to eating fiber? After all, it sounds so wonderful – there must be something bad about it, right? Well… there is the gas produced by soluble fiber fermentation, but that seems a small price to pay compared to the many benefits that fiber intake can have. Sorry to sound unbelievable, but no, in my opinion, there aren’t any real downsides. Actually, I’ll rephrase – there aren’t any downsides to eating the amount of fiber you get from the kinds of foods people eat, so long as you still get the necessary amounts of protein and other nutrients, too. Switch to eating entirely fiber-rich grasses instead of the normal grains, fruits and veggies and you might not fare so well. The only thing I will recommend, though, is that if you plan on dramatically increasing your dietary fiber intake, do it somewhat slowly to allow your body to adjust to the rise in non-digestible material in your diet. This will help you prevent the only known clinical side effects of sudden, high-fiber intake – tummy trouble.
Previous posts in the Understanding Our Bodies series:
Leathwood P, & Pollet P (1988). Effects of slow release carbohydrates in the form of bean flakes on the evolution of hunger and satiety in man. Appetite, 10 (1), 1-11 PMID: 3355122
Ruottinen S, Lagström HK, Niinikoski H, Rönnemaa T, Saarinen M, Pahkala KA, Hakanen M, Viikari JS, & Simell O (2010). Dietary fiber does not displace energy but is associated with decreased serum cholesterol concentrations in healthy children. The American journal of clinical nutrition, 91 (3), 651-61 PMID: 20071642
de Mello VD, & Laaksonen DE (2009). [Dietary fibers: current trends and health benefits in the metabolic syndrome and type 2 diabetes] Arquivos brasileiros de endocrinologia e metabologia, 53 (5), 509-18 PMID: 19768242
de Munter, J., Hu, F., Spiegelman, D., Franz, M., & van Dam, R. (2007). Whole Grain, Bran, and Germ Intake and Risk of Type 2 Diabetes: A Prospective Cohort Study and Systematic Review PLoS Medicine, 4 (8) DOI: 10.1371/journal.pmed.0040261
Pereira, M. (2004). Dietary Fiber and Risk of Coronary Heart Disease: A Pooled Analysis of Cohort Studies Archives of Internal Medicine, 164 (4), 370-376 DOI: 10.1001/archinte.164.4.370
Rimm, E. (1996). Vegetable, fruit, and cereal fiber intake and risk of coronary heart disease among men JAMA: The Journal of the American Medical Association, 275 (6), 447-451 DOI: 10.1001/jama.275.6.447
Brown L, Rosner B, Willett WW, & Sacks FM (1999). Cholesterol-lowering effects of dietary fiber: a meta-analysis. The American journal of clinical nutrition, 69 (1), 30-42 PMID: 9925120
MELLEN, P., WALSH, T., & HERRINGTON, D. (2008). Whole grain intake and cardiovascular disease: A meta-analysis Nutrition, Metabolism and Cardiovascular Diseases, 18 (4), 283-290 DOI: 10.1016/j.numecd.2006.12.008
Fuchs, C. (1999). Dietary Fiber and the Risk of Colorectal Cancer and Adenoma in Women New England Journal of Medicine, 340 (3), 169-176 DOI: 10.1056/NEJM199901213400301
Almost everyone has heard of Insulin. You probably know that people with type 1 diabetes need to inject themselves with insulin to survive, and must constantly monitor the amount of sugar they eat. But what do you really know about insulin? What is its purpose in the body, and why do we need it? How does it relate to our diets? What happens when things go wrong with it? And why should anyone who doesn’t have diabetes give a hoot?
Insulin is one of the most important hormones in the human body, and yet most people don’t really understand why our bodies make it or how what we eat affects the levels of insulin we produce. More so than any other hormone, our diet is key in regulating insulin levels, and thus a number of biological processes. As you’ll soon see, everyone should think about how what they eat impacts their body’s insulin release to be at their happiest and healthiest.
Why We Need Insulin
Every living thing requires energy to survive. In cells, energy is stored and shuttled around using a molecule called Adenosine Tri-Phosphate, or ATP. Whenever the cell then has an energy-requiring reaction, enzymes can use the energy stored in ATP’s phosphate bonds to fuel it. Cells rely on ATP to survive, and to create ATP, they rely on glucose.
ATP – the fuel for life
All cells, from bacteria and fungi to us, take glucose and use it to generate ATP by a process called Oxidative Phosphorylation. First, glucose is converted to an intermediate molecule called pyruvate via a process called glycolosis. As long as there is oxygen around, this pyruvate is further converted to Acetyl CoA, which enters a cycle of reactions called the Citric Acid Cycle. This takes the carbon to carbon bonds and uses them to create high energy electrons, which are then passed down a chain of enzymes which use the electron’s energy to create a proton gradient, the force of which fuels ATP synthase, the enzyme which creates ATP from ADP. Without glucose, cells cannot create ATP, and eventually die.
In plants, a process called photosynthesis takes light energy from the sun and uses it to combine carbon dioxide (CO2) and water (H2O) to create glucose (C6H12O6). This means that to survive, all they need is light, air and water. Unlike plants, though, we cannot create our own glucose, so we rely on our diets to provide it for us.
Just about everything we eat is able to be used to create glucose. Carbohydrates, by definition, are sugars, and all sugars are readily converted to glucose. The amino acids that make up proteins can be converted to glucose via an enzymatic process called gluconeogenesis. Fats, too, are converted to glucose or its derivatives; glycerol, for example, can be converted to glucose via gluconeogenesis, and fatty acids can be converted to Acetyl CoA via beta oxidation. No matter where it comes from, the glucose from our meals then ends up in our blood to travel around our bodies to the tissues that need it.
Obviously, having a blood glucose level that is too low would be bad – not enough glucose will get to our various tissues, and our cells won’t be able to generate enough ATP to function. This is a condition known as hypoglycemia, and the effects can range from mildly ‘feeling bad’ to seizures, unconsciousness, permanent brain damage or even death, all of which are due to a lack of ATP. But you can tip the scale too far in the other direction, too. You would think that since it’s so important, we would want a ton of glucose in our blood, but too much causes our blood to thicken, slowing it down and drawing fluid from our tissues to try and make it thin again. Too high of a blood glucose level, called hyperglycemia, can result in blurred vision, fatigue, dry mouth and heart problems that can sometimes be fatal. So our bodies work very hard to maintain our blood glucose levels between 3.6 and 5.8 mM (mmols/liter). This is about enough glucose to provide energy to the body for 20-30 minutes, so as we use up the glucose in our blood, our bodies constantly release more (hopefully) without overdoing it.
It’s particularly important for our bodies to maintain glucose levels every time we eat. Whenever we ingest food, our bodies have to quickly adjust to the sudden flood of glucose entering our systems as our meals are digested. Take something as small as a roll of Smarties, for example. One roll of Smarties contains 6 grams of sugar. At around 125 lbs, my body contains an average of 4 liters of blood. This means that if all the sugar from a single roll of those delicious candies were to enter my bloodstream at once and remain unchecked, it would raise by blood sugar by 8 mM! Four smarties packs, and my blood sugar levels would be fatal. So why, then, when I enjoy a sugary treat, do I not go into severe hyperglycemia?
The answer is insulin. Our bodies release insulin right before and during eating, and that insulin tells our bodies to start taking glucose out of the blood, thus lowering our blood glucose levels. It does this by both promoting uptake of glucose by cells and the storage of glucose within our cells. Without insulin, we would all go into hyperglycemic shock and die from something as common as a hamburger.
What is Insulin?
Insulin is a relatively small peptide hormone produced by β-cells in the pancreas. It’s main job is to signal the liver, muscle and fat tissues to take up glucose from the blood and store it as glycogen. As the glucose level in the blood drops to normal, insulin release slows or stops. If it drops too low, an antagonistic hormone, called glucagon, is released which does the opposite of insulin, stimulating cells to break down glycogen and release glucose.
The insulin and glucose process illustrated
But insulin does much more than just control blood glucose levels. Its effects depend on the cell type that receives its signal. Fat cells, for example, don’t take up or store glucose. Instead, they respond to insulin by taking the fats that enter the blood stream and turning them into fatty acids, which they store in large vacuoles. Thus insulin promotes the uptake and storage of fat in our adipose tissues. While insulin levels are high, our bodies don’t digest or use fats for fuel. Instead, we rely on the glucose in our blood and tissues. This is key to keep in mind when trying to lose weight – you body simply won’t break down and use your fat reserves with insulin around.
Furthermore, insulin stimulates the body to absorb most amino acids. However, it doesn’t lead to intake of tryptophan by cells. This creates an effective rise in tryptophan concentration in the blood, allowing it to pass through the blood brain barrier. In the brain, tryptophan is converted to serotonin, a neurotransmitter whose primary purpose, in this case, is to reduce appetite. But serotonin has a lot of other effects, as those of you who have read the previous Understanding Our Bodies on Serotonin know well. In general, increased serotonin leads to a feeling of happiness and calm, which is why we get such satisfaction when we eat. Thus insulin is important not just when it comes to dealing with fats and sugars but in regulating our emotions, too!
It turns out insulin in the brain has a lot of functions, very few of which we understand well. Mice that lack insulin and leptin receptors in their brains, however, exhibit insulin resistance that is characteristic of diabetes. Strangely, though, they have a lot of reproductive deficiencies, too – the females have poor fertility, high testosterone levels and deformed ovaries, for example. Why insulin has these effects on reproduction is unknown, but it just goes to show that insulin does a lot more than regulate blood sugar levels, and is far more important in our bodies than we once thought.
Regulating Insulin
While insulin levels are mostly regulated by the amount of glucose in our blood, other things can stimulate its release. Other molecules from digestion, like certain amino acids, proteins and lipids, can similarly stimulate insulin release. But most incredibly, our bodies begin releasing insulin before we even take a single bite of food. When we think about, smell, or slightly taste foods, our brains trigger what is called Cephalic Phase Insulin Release. A food’s color, appearance, flavor, aroma, and texture can all impact how our brains respond to the idea of eating it. The goal is to prepare the body for what the brain thinks will be a sudden flood of glucose. The sweeter and sugarier the brain thinks the meal will be, the more insulin it stimulates the pancreas to release before the food even enters the mouth.
Merely waiting in line for food can ramp up the body’s insulin system – credit, flickr -Eleets121
Once we start to eat, our bodies ramp up insulin secretion, in what is often called first phase insulin release. Insulin that was kept in storage while our blood glucose levels were normal is released all at once, leading to a dramatic increase in insulin levels. The amount of insulin secreted in the first phase response to a meal is determined by the amount of glucose encountered in the previous meal – the more you needed last time, the more is released in this first phase. In a healthy person, this first phase response peaks a few minutes after you’ve started your a meal.
The β-cells then take a quick pause. If the first pulse was enough, then they slowly take up the insulin they released, and store it for the next meal. If the blood glucose levels stay high, though, the β-cells begin producing and releasing insulin in pulses every ten to twenty minutes. They continue this until the body’s blood glucose gets back to normal levels. The blood sugar rise caused by the meal peaks about half an hour after eating, and this, in turn, leads to a decrease in insulin production and release.
There are other regulators of release of insulin, too. Stress hormones like noradrenaline inhibit insulin release. This makes sense when you think about it evolutionarily. The purpose of stress hormones is to prepare our bodies for a sudden need to act. If we see a tiger, for example, our stress hormones spike so we can be prepared to fight if it attacks or run like hell to get away. Either way, we’ll need extra energy on hand to deal with the stressful situation, so stress hormones stop insulin from being released to ensure that a little extra glucose is in the bloodstream and able to reach whatever body parts need it most.
Not all insulin is produced in the pancreas, though. The brain also produces its own supply of insulin. The brain is a complex organ and needs lots of fuel to run properly. Insulin in the brain enhances learning and memory. Meanwhile, reduced levels of insulin and its related proteins are linked to Alzheimer’s disease and other degenerative disorders.
Insulin and Disease
Insulin is at the heart of many diseases. As I just explained, insulin in the brain is particularly key, and can lead to neurological disorders. But too much or too little insulin in the body is a big problem, too. There is a special name for the series of diseases caused by impaired insulin signaling in the body. You might have heard of it: Diabetes Mellitus.
When your body stops producing insulin, injections are all that is left – credit, i5a, flickr
Diabetes occurs when the body does not have the insulin signaling it should. There are two major types: type 1 and type 2. People with type 1 diabetes tend to realize their condition early in life, and must deal with it throughout their lifetime, while those with type 2 tend to develop symptoms later on. What’s the difference? While both conditions involve problems with the insulin pathway, type 1 diabetes is caused by a lack of insulin, while type 2 is caused by chronically high levels. People with type 1 diabetes have innately low levels of insulin due to genetic mutations. Without the ability to produce enough of this vital hormone, they usually have consistently high blood glucose levels. While this is a problem, there are many forms of treatment, including insulin injections. By carefully controlling their sugar intake and taking insulin when they need it, people with type 1 diabetes can regulate their blood glucose levels to being almost normal.
Type 2 diabetes is different. Type 2 diabetes results from the body having high insulin levels for too long. Insulin is meant to be a fast acting hormone – you release it when glucose levels are high, so that they drop. Then the signal stops. If you constantly eat too much or have a very sugary diet, you can end up with high insulin levels all the time. This leads to the body becoming desensitized to insulin. It’s kind of like trying to listen to a radio with static. If you only get a little static every once in a while, you can hear the song fine, and understand what the artist is saying. But start having high static all the time and you can’t tell what song is playing anymore. Your body, in effect, can’t tell what signal it’s supposed to be getting, and instead stops listening all together. Type 2 diabetes is that much more dangerous because the body will rarely respond to insulin treatment, meaning that drastic diet changes and exercise are the only ways to fight back.
Sadly, more than 90% of diabetes cases are type 2. Prevalence rates of type 2 diabetes doubled between 1990 and 2005, causing the CDC to declare it an epidemic.
Insulin is also a key player in Metabolic Syndrome. Metabolic syndrome, often called prediabetes, is poorly characterized, and even more poorly understood. Symptoms include elevated blood pressure, high blood cholesterol, and increased waist circumference. The main cause appears to be decreased response to insulin in certain tissues, specifically muscle and fat. The thing is, we’re not sure if it’s treatable or an irreversible first step in Type 2 diabetes. Often, people with metabolic syndrome are overweight, and at higher risk for other, even more life threatening conditions like heart disease. While some drugs can be prescribed to treat the symptoms like high blood pressure, the only long-term solution is to lower chronic blood glucose levels and restore insulin sensitivity, if, indeed, it can be restored at that point.
Nutrition and Insulin: Glycemic Indexes, Glycemic Loads and Beyond
Everyone should think about insulin and blood glucose levels, not just people with diabetes or metabolic syndrome. What we eat, how much of it, and when can impact our insulin release, which in turn can have a big impact on our bodies and how we feel.
Refined carbohydrates like spaghetti can exacerbate blood sugar issues – credit, flickr, Bxl06
The major dietary players in insulin regulation are carbohydrates. While fats, proteins and everything else can increase blood glucose levels, carbohydrates do it much faster for two simple reasons: firstly, they’re one of the first things we break down in digestion. There are enzymes in our saliva that begin carbohydrate breakdown before the foods even reach our stomachs! But more importantly, carbohydrates lead to immediate rises in blood glucose because theycontain glucose. Other molecules must first be converted to glucose, but carbohydrates, which include sugars, just need to be hacked into pieces by our digestive enzymes. Different carbohydrates contain different amounts of the monosaccharides, like glucose or fructose. Thus they each have different impacts on immediate rises in blood glucose levels.
This difference in effect on blood sugar level is the basis of the Glycemic Index, or GI. The glycemic index rates foods based on how much of an immediate impact they have on blood glucose per 50 grams of carbohydrate. If you picture the rise in blood glucose levels in response to a food on a graph over time, the glycemic index is a number that is related directly the area under a two-hour curve. The higher the spike in blood glucose levels, the larger the area under the curve is, and thus the higher the glycemic index, which is somewhere on a scale of 1 (low) to 100 (high). Most foods that have a low GI induce lower spikes in insulin, but not all of them. There is another index, called the Insulin Index, that looks directly at rises in insulin levels. While the glucose and insulin scores of most foods are related, high-protein foods and baked goods that are rich in fat and refined carbohydrates usually elicit much higher insulin responses than their glycemic index values would suggest.
Research into the glycemic index have found strong support of the idea that low GI foods are better for us. People who eat less high GI foods have lower risks of developing both type 2 diabetes and heart disease. It’s uncertain if this is due to overall lower blood sugar levels or reduced glycemic “spikes.” When glucose levels increase dramatically, our bodies ramp up the release of insulin and the processing of glucose from the blood, including ATP generation. While ATP is great, the process by which we make it – oxidative phosphorylation – has side effects. Mainly, the faster it’s churning, the more likely the machinery is to leak reactive oxygen species (ROS). These oxygen radicals are highly reactive and tend to transform whatever they come in contact with, which can cause damage to proteins, membranes, or even our DNA. By eating foods that increase glucose levels more slowly, we limit ROS bursts that can damage our cells.
The glycemic impact of foods can be strikingly different for your body
However, the glycemic index isn’t perfect. Glycemic indices aren’t the whole story since they are based on a per-carbohydrate basis. Two foods that have the same GI can have dramatically different effects on blood glucose per serving if one has significantly higher carbohydrate content than the other. The affect a serving of food has on blood glucose is referred instead to its Glycemic Load. Glycemic load is calculated by multiplying the weight (in grams) of carboydrate in a serving by the food’s overall GI and divided by 100. A GL of 10 or less is considered low, while 20 or more is considered high. Let’s say you want to eat a baguette, for example. Both whole gain and French baguettes have similar GIs (roughly 73). But there’s a lot less carbohydrates per serving in the whole gain loaf, and thus its GL is only 9 while the GL of the french baguette is 27!
The GI or GL of a food isn’t the only thing you should consider when it comes to insulin and your diet. When you eat matters a lot, too. Our bodies react to the same foods differently at different times of day. Morning is a special time for your body because you’ve just spent a while in a comatose state. The changes your body undergoes while you sleep can have a dramatic impact on how it responds to food. Insulin levels tend to be low in the early morning, for example, because your body releases stress hormones just before you wake up. Once you’re awake, though, your body ramps up insulin secretion to metabolize the high glucose levels and give your cells a little fuel to start the day with.
These alterations have a big impact on how our diets affect us. When different foods were tested for their GI values at different times of the day, for example, researchers found that the same food eaten for lunch instead of breakfast induced a lower glucose response. This is why it may be particularly important to eat a protein-rich breakfast, like eggs, instead of high glycemic foods like white bread toast. Time of day has been found to have a larger effect on insulin responses in women than in men, though no one understands why. Furthermore, studies have shown that the quality of sleep you get affects how strongly your body reacts to food. A restless night can lead to higher glucose responses and larger spikes in insulin in response to food in the morning. So getting a good night’s sleep is also important in preventing the kinds of spikes which may be a major factor in type 2 diabetes.
Also, foods can interact with each other to lower or raise the GI values of a meal. For example, foods that contain fiber, protein, or fat will generally reduce the GI of the meal as a whole. Recent studies have even shown that having a small volume of alcohol (one drink) prior to a meal reduces the GI of the meal by 16-37% – which, as far as I’m concerned, is fantastic news. Furthermore, many cultures eat high GI foods like potatoes or rices but have low occurrences of diabetes and obesity. The truth is we have yet to tease out all the factors that lead to these conditions, and the GI level of our diets is likely only one of many related factors.
The Even Bigger Picture
Clearly, what we eat, with what and when matters a lot when it comes to insulin levels. This is important in keeping healthy and reducing the risk of metabolic syndrome and type 2 diabetes. But insulin affects so many other things in our bodies, from amino acid uptake to fat storage. We need to consider insulin whether we’re worried about type 2 diabetes or not!
Thinking about how our diet affects insulin is especially key when trying to lose weight or maintain a healthy weight. Insulin actually triggers the storage of fats in adipose tissues, so sustained high levels of insulin promote weight gain! Furthermore, recall that our bodies don’t break down fat while insulin is circulating. This means that if we eat foods with high GIs that produce sustained insulin levels, we’re shooting ourselves in the foot, even if we eat less calories overall.
Understanding how our bodies regulate insulin release also explains why certain foods are worse for us than we’d expect. Sugary drinks are particularly bad for us, for example, even when we take into account their calorie and sugar content. This is because our brains don’t judge their sugar content well in advance. Thousands of years of evolution led our brains to believe that drinks, overall, were low-cal things that mostly contain water. Our brains aren’t wired to think that fluids contain a lot of sugar. Thus when we look at a soda or even begin to sip one, we don’t have the same level of cephalic phase insulin release or first phase insulin release that we would for a solid treat. The end result of this is that our bodies are unprepared for the sudden sugar rush, and have to instead release a massive amount of insulin all at once to deal with what it considers an inexplicable rise in blood glucose.
High spikes in insulin lead to dramatic drops in blood glucose, which can cause your body to feel hungry sooner. Eating low GI and GL foods can help you lose weight by making you feeling fuller longer. Low GI foods don’t cause dramatic drops in glucose levels, thus you tend eat less throughout the day. It’s thought that this effect, on top of the high-sensitivity of our bodies to high GI foods in the AM, is why eating eggs, a low GI food, instead of cereal or toast in the morning has been found to reduce overall food intake for the day by as much as 18%. You can create lower spikes in insulin not only by avoiding sugary drinks and eating lower GL foods but also by eating smaller meals. This is because the amount of first phase insulin release is dependent on the amount of insulin needed for the previous meal. The bigger meals are, the larger the spike at the beginning of every meal, and the bigger the drop in glucose afterward.
But you shouldn’t just cut out everything that leads to insulin release! Insulin is important, and too little is just as bad as too much. Even small drops in daily insulin levels can affect us negatively. For example, dieters often experience depression around 2 weeks after they begin cutting high-glycemic foods like carbohydrates out of their diet. Why? Because they have much lower levels of insulin than they did before. Decreased insulin means decreased amino acid uptake, and because the level of other amino acids affects how well tryptophan crosses the blood brain barrier, decreased insulin means less serotonin which leads to, in layman’s terms, feeling like crap. While you should monitor the GI of your meals to reduce insulin spikes, you shouldn’t go for rock bottom either. At least you shouldn’t if you want to be happy about it!
Previous posts in the Understanding Our Bodies series:
Van Cauter E, Polonsky KS, & Scheen AJ (1997). Roles of circadian rhythmicity and sleep in human glucose regulation. Endocrine reviews, 18 (5), 716-38 PMID: 9331550
Hill, J., Elias, C., Fukuda, M., Williams, K., Berglund, E., Holland, W., Cho, Y., Chuang, J., Xu, Y., & Choi, M. (2010). Direct Insulin and Leptin Action on Pro-opiomelanocortin Neurons Is Required for Normal Glucose Homeostasis and Fertility Cell Metabolism, 11 (4), 286-297 DOI: 10.1016/j.cmet.2010.03.002
Spiegel K, Knutson K, Leproult R, Tasali E, & Van Cauter E (2005). Sleep loss: a novel risk factor for insulin resistance and Type 2 diabetes. Journal of applied physiology (Bethesda, Md. : 1985), 99 (5), 2008-19 PMID: 16227462
Brand-Miller JC, Fatema K, Middlemiss C, Bare M, Liu V, Atkinson F, & Petocz P (2007). Effect of alcoholic beverages on postprandial glycemia and insulinemia in lean, young, healthy adults. The American journal of clinical nutrition, 85 (6), 1545-51 PMID: 17556691
Ratliff J, Leite JO, de Ogburn R, Puglisi MJ, VanHeest J, & Fernandez ML (2010). Consuming eggs for breakfast influences plasma glucose and ghrelin, while reducing energy intake during the next 24 hours in adult men. Nutrition research (New York, N.Y.), 30 (2), 96-103 PMID: 20226994
The most common advice as to how to lose weight given my doctors to people that are overweight or obese is to cut calories. Reduced caloric intake has been lined to all kinds of health benefits, from extended life span to reduced risk of heart disease. But the primary goal of people who slice their caloric budget is to lose weight.
Empty Plate, by iamchanelle, flickr
In principle, this makes perfect sense. Your body uses the calories you eat to fuel its metabolism. Eat less food, and the body must make up for the lack of fuel somehow, ideally, by beginning to digest stored fats that were deposited in specialized cells when the you were eating more food than your body needed.
But as anyone who has tried to diet knows, it never seems that simple. Even when you are as loyal to your diet as you can be, you never seem to lose the kind of weight you want. Now, new research out of the Oregon Health and Science University may explain the discrepancy between theory and reality. They found that, at least in some of our closest relatives, cutting calories isn’t enough because the body compensates for the reduced intake by lowering activity levels.
The Study
Because controlling diet in people is notoriously difficult, the OHSU research team used a primate model to determine how well reducing calorie intake in adults works as a weight loss strategy. They took 18 female macaques and fed them a high-fat diet for several years, allowing the monkeys to pack on the pounds. They then cut their dietary fat intake dramatically, leading to a 30% reduction in calories. They monitored the monkeys’ weight and activity levels over time to see if the change in diet caused the animals to lose weight.
The Results
Instead of losing weight, the calorie-restricted macaques got lazier. Indeed, despite cutting almost a third of the calories from their diet, the macaques didn’t lose any weight at all in the first month. When researchers cut their calorie intake even more, down another 30% for the second month, the same thing happened. There was a little weight loss during the extreme calorie cutting, but not much, and instead there was much less activity. Meanwhile, a control group that was forced to run on a treadmill for an hour every day lost plenty of weight, even though the treadmill had no effect when they were on the high-fat diet.
What It Means For Us
Everyone wants to believe that if they just cut back a little, they’ll lose weight. Yet time and time again we’re reminded that diets almost never work. Perhaps part of the problem is that while we focus on cutting things out, we forget that we need to keep up our body’s energy utilization for the lack of calories to have any effect. The body has many natural mechanisms to conserve energy during times of food shortage. Decreasing activity levels are likely just one way in which our bodies compensate for perceived starvation. While this was great for the chaotic and troubled paleolithic man, it gets in out way when we try to slim down in a fat-filled, food-plentiful modern society. So if you’re trying to lose weight, instead of just changing your diet, be sure to keep up an exercise regimen that will force you to keep active. You don’t have to work out four hours a day or anything – just do something that ensures that you use up some energy and don’t just sit around. That way your body feels the need to use your fat stores for fuel, and you see what you expect from being faithful to your diet.
Citation: Sullivan, E., & Cameron, J. (2010). A rapidly occurring compensatory decrease in physical activity counteracts diet-induced weight loss in female monkeys AJP: Regulatory, Integrative and Comparative Physiology, 298 (4) DOI: 10.1152/ajpregu.00617.2009
It’s estimated that ninety-eight percent of attempts to lose weight fail. Ninety-eight percent. That’s a sobering statistic, especially in a country where sixty-seven percent of adults and almost twenty percent of children are overweight. It’s even more shocking to think that the secret to losing weight and getting healthier isn’t a secret at all. We all know what we can do to improve our bodies: just eat better.
Why is it so hard for us to eat a healthy diet? It would appear to be the easiest solution in the world. Just choose wisely at the grocery store and – Poof! – you can feel better, lose weight, and look fantastic. Of course, we all know that eating healthy is never as easy as it sounds. So what is in the way of making good food choices?
The answer is we are. When we try to eat healthy, we’re picking fights against our own brains. Instead of working through those arguments, we make excuses. While we say we want change, the truth is that there are a number of reasons that we don’t. We can’t eat better until we understand why, deep down, we don’t actually want to. It’s time to sit down and work through our issues and excuses when it comes to healthy food so we can finally get past them and choose a healthier lifestyle.
We Think Healthy Foods Are Gross (Even If They’re Not).
Let’s be honest – most of us think that health foods aren’t the tastiest items on the menu. When school kids were asked what foods they dislike, for example, every single one named a vegetable. Health foods are those things we think we have to eat, but really don’t want to. We don’t choose to eat them – and why would we? They’re stiff, chewy, and tasteless. In short, they’re gross.
I can hear you now – I don’t think that! you’re saying. Guess what? You probably do, at least unconsciously. Even adults who might think they’re unbiased fall into the trap of thinking healthy foods taste bad. Tell someone that cheese or yogurt is low in fat, and they’ll say it doesn’t taste as good as the higher-fat version, even if the two items are the exact same thing. Or, take soy items, for example. Studies have found that merely labeling a foodstuff as containing soy will make people claim that it is grainy, less flavorful and has a bad aftertaste even if it doesn’t contain soy. Simply implying that a food is healthy alters how it tastes to us through a complex interaction between our tastes and our brains.
It’s not your fault that you think less of good foods – you’ve been trained to think that way. The key to beating your brain is not to focus on how much fat or whatever is in a food, but instead get used to buying healthy foods without counting their calories. If you can find a way to buy healthy items just because (making meals that include them, for example) instead of because they contain less grams of fat than another, you might just find that your meals taste better even though you’re eating healthier foods.
We Think We Don’t Have The Time To Eat Better
Most people feel their tables are at least this busy
Even if it’s not the taste of healthy foods, there always seems to be an excuse to not eat better. Most often, we blame our bad habits on a lack of time. A survey of Europeans, for example, found that the most commonly cited reason for eating poorly was that people claimed they didn’t have time to make healthy food. A similar survey in Minnesota found that almost fifty percent of participants claimed not to have the time to eat better.
C’mon, admit it – this is just pure, sweet B.S. The sheer idea is strange – after all, how much time does it take to “make” a piece of fruit as a snack? Does it take more time to prepare a banana than a bag of chips? Healthy foods are often quick to cook (or require no cooking anyway), and even those that aren’t are no more labor intensive than unhealthy options. The idea that healthy foods take more time is just in our heads.
Instead of worrying about the time it’ll take to eat better, buy healthy foods that are cheap and easy to make. Fruits are great in this respect – they’re ready to go when you want a bite to eat. Besides, even if it does take more time to prepare a good meal, isn’t it worth it to be healthy? Once you truly make the choice to make a change, any small sacrifices in time won’t even be noticed.
We Think Healthy Foods Are Too Expensive
This is a big one for many people, and is cited almost as often as a lack of time as a barrier to eating better. How can you be expected to eat healthier when health foods cost so much? We’re in the midst of a recession here – we can’t afford to splurge!
Money is a common excuse for eating poorly
Well, if you’re talking about organic or specialty foods, then yes, you’re right – these foods do cost more. But you don’t have to eat organic or from the health food section to eat better! There are a lot of ways to eat better without shelling out extra cash. Increase your intake of cheap health foods like eggs or frozen veggies. Frozen foods can often be bought in bulk and have the nifty property of not getting rotten if you don’t make them that day, so they rarely go to waste. Furthermore, you can buy most health foods as generic supermarket brands instead of the brand name items. Guess what? You’ll never notice the difference.
You can even save money by eating healthier. For example, stop buying juices, sodas and other bottled drinks and buy an aluminum water bottle instead. Almost every drink you might consume is high in calories and sugar, and even if they’re not, they’re definitely more expensive than tap water. Also, one way to make sure you don’t spend too much is to make a list. If you plan ahead and stick to it, you won’t give into the temptation of that bag of cookies just because you’re hungry. Planning ahead will also help keep you from overeating because you won’t feel a need to eat whatever has been lying around the house for awhile – and eating less will not only help with your bottom line, it’ll help with your bottom.
Why Choice Matters
The point of all of this is that we have to make the choice to eat better, not try to force ourselves to. Why is it so important that we want to eat healthier foods? Scientists have found that choice plays a big role in how our bodies react to eating something. For example, researchers from the University of Chicago found that when they told study participants that a new snack item was “tasty,” they reported feeling fuller than when they were told the exact same food item was “healthy.” In fact, the subjects who were given the healthy-labeled treat reported feeling hungrier than those who ate nothing at all. Simply telling them the item was good for them made them feel like they had to eat more food. I think we’ve all been there before: you get yourself a healthy snack, only to raid the fridge later when you’re still hungry. It’s not that the snack wasn’t enough; it’s that you had it in your head before you ate it that it wasn’t going to be satisfying. We set ourselves up all the time for this kind of self-fulfilling prophesy.
But there was a twist: when people were allowed to choose whether to try the healthy snack or the tasty one, those that chose the healthy snack freely reported feeling just as full as the others. In other words, when forced to eat healthy, the participants felt hungry; when they chose to eat healthy, they didn’t. So all you have to do to make the most of healthy eating is actually want to eat healthier foods.
Here are some tips to help you choose a healthy diet, not box yourself into one:
1. Figure out what is keeping you from eating better. Take a month and write down what you eat every day, and how you feel when you eat. By taking notes you allow yourself to look into how you really feel about your diet. Are you begrudging healthy options? Making excuses for bad behavior? Are there healthy foods you love? These are important things to know. Once you’ve diagnosed your issues with healthy eating, you can work towards getting through those issues and simply eating better. If money is an issue, for example, you can take some time to figure out what you actually spend on groceries every month, and then pick healthier foods that don’t go over budget. You can’t fix problems until you know what they really are.
2. Focus on the positives. Don’t think about how you’re going to have to give up something you love, think about how you’re going to gain something better, like money saved by cutting out sodas. Or, reward yourself for doing well. Maybe you can use the money you save to buy a new outfit that will fit a slimming you. Or set a goal that you’ll give yourself a bonus yourself for achieving – like commit to buy a new camera when you’ve stayed on track for a few months to take pictures of your soon-to-be fantastic new body at the beach. Give yourself some motivation to really want to do this! By thinking positively, you avoid the mental traps that bring people down when trying to eat better.
3. Find healthy foods that you honestly like to eat. Don’t sit there and try to eat brussel sprouts just because you think they’re good for you! Find a vegetable or fruit that appeals to you regardless of its healthy nature. Then look into how to use that food to attract you to other foods. For example, let’s say you like pineapples. Search for some recipes that use pineapples so that you’re more interested in healthy meals – like a pineapple curry (coconut milk has some great things in it). Or pineapple salsa to go on top of baked chicken. Use the foods you like to fuel your way into healthier meals instead of forcing yourself to eat things just because they’re healthy. And don’t be afraid to try new things! You don’t know that you won’t like something until you try it.
It all comes down to making healthy options more appealing. Figure out how to do that for yourself, and you’ll be that much closer to your goals.
Citations:
Zeinstra, G., Koelen, M., Kok, F., & de Graaf, C. (2007). Cognitive development and children’s perceptions of fruit and vegetables; a qualitative study International Journal of Behavioral Nutrition and Physical Activity, 4 (1) DOI: 10.1186/1479-5868-4-30
WESTCOMBE, A. (1997). Influence of Relative Fat Content Information on Responses to Three Foods Appetite, 28 (1), 49-62 DOI: 10.1006/appe.1996.0066
Wansink, B. (2000). How soy labeling influences preference and taste The International Food and Agribusiness Management Review, 3 (1), 85-94 DOI: 10.1016/S1096-7508(00)00031-8
Kearney, J., & McElhone, S. (2007). Perceived barriers in trying to eat healthier – results of a pan-EU consumer attitudinal survey British Journal of Nutrition, 81 (S1) DOI: 10.1017/S0007114599000987
Eikenberry, N., & Smith, C. (2004). Healthful eating: perceptions, motivations, barriers, and promoters in low-income minnesota communities Journal of the American Dietetic Association, 104 (7), 1158-1161 DOI: 10.1016/j.jada.2004.04.023
Finkelstein, S., & Fishbach, A. (2010). When Healthy Food Makes You Hungry Journal of Consumer Research DOI: 10.1086/652248
Once you start to understand the science behind a lot of diet, nutrition and health science publications, you realize that it’s rare for the recaps of science in the newspaper to accurately depict a scientist’s results or a study’s real-world implications. I’m not trying to take a shot at all health journalists – just a large number of them. I think they need to be called out for their shoddy reporting and exaggeration techniques. Take, for example, a recent study published in the Journal of Physiology. From the headlines it made, you’d think that scientists have stumbled upon a miracle workout regime:
Marathon or sprint? (credit, Frederic de Villamil, flickr)
Read a few paragraphs into each and you’ll be told that science has revolutionized how people should work out. “Alternating short bursts of intense activity with brief rest periods delivers more benefit for less exercise, research shows.” “A set of ten one-minute sprints on an exercise bike three times a week holds the same benefits as ten hours of ‘conventional’ distance cycling.”
Indeed, the articles even tell you that: “Tests afterward showed that their muscles had improved as much as if they had been involved in endurance training.”
The bottom line: research has reportedly shown that by working out for just ten minutes three times a week, you can be as in shape, if not more so, than quadrupling the standard thirty minutes a day five days a week.
Here’s a hint: if it sounds too good to be true, it probably is.
The Research: What They Did
All of these articles center around a recent paper in The Journal of Physiology titled, “A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms.” It centers around a recent fashion in workouts called High-Intensity Interval Training, or HIT. HIT is a method of exercise which involves working as hard as you can for brief intervals followed by brief rest intervals. For example, you might sprint for a minute and then jog for thirty seconds, and repeat this for a half and hour. The idea is that by doing higher intensity workouts for shorter time intervals, you can work out “less” but get the same, or even more, benefit.
Of course, that’s not what this study showed. The study at hand followed seven men with an average age of 21 through a two-week, lower-intensity HIT training regimen where volunteers rode a stationary exercise bike for 12 cycles of 60 seconds of peddling above their comfort zone followed by 75 seconds of rest. The researchers tested the volunteers’ levels of a number of fitness variables, including cycling time trials and the activity of exercise-related enzymes like citrate synthase and cyctochrome c oxidase. They also tested for increases in muscle glyocgen, GLUT4, and PGC-1α, which is a transcription factor that is proposed to be upregulated during muscle creation.
In a vast sweep, they found that the training increased everything that could be associated with increasing muscle and being more fit. They state that:
“this study demonstrates that a practical model of low volume HIT is a potent stimulus for increasing skeletal muscle mitochondrial capacity and improving exercise performance.”
The Research: What They Didn’t Do
You might have noticed that there’s no mention of what happened to the group that did 10 hours of moderate exercise instead of the HIT training regimen: that’s because it didn’t exist. The study did not, in any way shape or form, compare HIT to regular training techniques. Where did the headlines get the idea that this somehow beat 10 hours of conventional exercise? That’s a good question, because it isn’t in the paper. The paper’s last remarks are that future studies need to look into this type of exercise in further depth, “to determine whether this type of training is an effective health-enhancing exercise strategy.”
The Tortoise or the Hare? This study did nothing to clear up the debate.
The news coverage would have you think that this training method is somehow better than how you might normally work out, and yet the study doesn’t compare it to any kind of normal workout regime. They don’t even try to compare their results to other studies. They simply state that working out this way can be good, too. And are you surprised that adding an additional 15-30 minutes of high-intensity workouts a few times a week improves your health? After all, shouldn’t adding any kind of exercise improve something?
That’s not to say that high-intensity training isn’t potentially better than longer, low-intensity training. Studies have shown that improvements in many exercise variables are directly related to intensity, duration, and frequency of training. In short, the harder you work, the better it is for you, and you don’t have to work as long to achieve the same results. In principle, this makes sense: a half hour run is going to do more for you than an hour walk. The question is how hard do you have to work for how long and how often to get the kind of results you want – and the answer to that isn’t anywhere in this paper.
The point is that this study didn’t test how long moderate training took to equal the interval training results, or compare the interval training to a given, conventional training regimen. It didn’t show that HIT improved fitness more or less than any other method, nor more or less quickly. For that matter, it worked with young, fairly in shape men, so its application to the masses is very limited. Is it better for a 60 year old, overweight woman to undergo a HIT workout than power walk around her neighborhood every morning? No one knows – it hasn’t been studied.
Don’t Judge A Study By Its News Coverage
The take home message is that you can’t believe everything you read in a newspaper. Scientific studies are, more often than not, couched in a way that the journalists will think is eye-catching, even if it distorts the actual study’s findings. The goal of these journalists isn’t to pass on vital information. It’s to gain as many readers as they can without being so false as to get in trouble. Indeed, sensationalized headlines get attention, but they do so in the wrong way. They make the science unimportant and diluted, and lead to a mistrust of scientific research. After all, if every day you’re told that scientists are a day away from curing cancer, but a cure still isn’t there, you start to think that the scientists are full of crap. But it’s not the scientists that are full of it – it’s the journalists that blow findings out of proportion and skew results in whatever way they think will sell articles. Even worse, the mainstream journalists do so without linking to the actual studies – meaning you can’t even click on a link and read the paper’s abstract to see if the article written about it is doing it justice. That’s simply unacceptable.
Little, J., Safdar, A., Wilkin, G., Tarnopolsky, M., & Gibala, M. (2010). A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms The Journal of Physiology, 588 (6), 1011-1022 DOI: 10.1113/jphysiol.2009.181743
“Pain in the abdomen. Splitting Headache. Nausea and vomiting. Choking and couldn’t get their breath. Coughing up blood.” Phone calls like these broke the dawn of a fall day in the mill town of Donora, Pennsylvania back in October, 1948. Already two had died and another 18 were soon to follow. The death toll would have been far higher if not for a couple brave firemen filling oxygen tents as quickly as they could. Still, no one was quite sure what was going on. Only later would it be discovered that the thick smog covering this Appalachian valley was due to a severe temperature inversion. Its killer characteristic? Fluoride.
The Fluoride Deception’s Cover
Few public health issues in American history have riled people quite like fluoride. Its story is replete with famous figures in American history, dramatic tales from the Manhattan Project, corporate cover-ups, redacted research, shattered careers of those that spoke against it’s use and the tragedy at Donora in 1948. The tide that binds all these accounts together is a fascinating book called, “The Fluoride Deception” by Christopher Bryson. His work paints a picture with enough intrigue to be nominated for an Oscar but remains deftly aware of itself long enough to stay away from hyperbole – most of the time at least.
Fluoride, The Way Low Down
The Fluoride Deception by Christopher Bryson
Bryson takes his readers on an exhaustive journey of the molecule through the eyes of those that have known it first hand. We learn the perils of researching the subject from carefully placed protagonists like scientist Dr. Phyllis Mullenix, whose entire career was derailed by publishing information about fluoride’s neurotoxic effect at disturbingly low concentrations [1], and Kah Eli Roholm, a Danish pioneer in the research of fluoride’s effects and publisher of the groundbreaking work, Fluorine Intoxication [2], back in 1937. Shady, villain-like characters named Dr. Harold Carpenter Hodge and Dr. Robert A. Kehoe act as provocateurs in the background, silently pushing a pro-fluoride agenda with their work – at the behest of the Department of Defense’s Manhattan Project and major fluoride users like US Steel and Alcoa.
Intrigue is definitely a current running through the text – and it helps readability. Bryson works hard at establishing the links between the industrial uses of fluoride and its eventual role in water fluoridation. His case is circumstantially strong as the middle of the book describes the legal wrangling mill workers would endure to get compensation from corporations using fluorides industrially in the workplace. But what comes away as the most surprising aspect of his account is how the type of fluoride used in water fluoridation is actually just fluosilicic acid, a toxic byproduct of aluminum smelting and other heavy industrial processes. It becomes clear here that the waste is being dumped into the water supply in lieu of having to dispose of it in some other way.
Given most people’s proclivity for considering fluoride as a beneficial tooth decay reducer, his evidence is both striking and damning. You can reserve judgment temporarily against toothpaste, as it uses sodium fluoride as its preferred molecular combination – not fluosilicic acid, but still take a moment with the thought of people using the water supply as a dumping ground. For just for this insight alone, you would be remiss not to pick up the title. However, for those of you with a scientific nose, it is the moment just after you make the connection between water fluoridation and fluoride’s industrial uses that will both haunt and fascinate you as the book continues. It will also be the moment after which this book’s value to the discussion notably decreases.
Crying for More, Crying for Less
Once you wrap your head around the arguments Bryson is making in the book, it starts to fit the vicious battle some people wage against water fluoridation. For the most part, the battle against fluoride is mostly a cold war, although the occasional community, like Southampton in the UK recently, will organize itself in protest of water fluoridation. Frankly, it’s amazing more hasn’t been said here in the US about its use, although there is certainly an underground resistance to its use, spearheaded by the Fluoride Action Network.
Dr. Frederick McKay, the first person to make the connection between fluoride and cavities
This evolved agency view comes from a series of observations by Dr. Frederick McKay throughout the early 1900s that showed areas in the Western US, where calcium fluoride levels in the water are naturally higher, exhibited stained teeth with far less decay than areas with less fluoride in the water [3]. Landmark studies corroborated these views, especially the 1945 study involving the first test case in Grand Rapids, Michigan that showed adding sodium fluoride to water resulted in up to 54% fewer cavities [4].
All of this early science on the subject was an issue Bryson mostly avoids, to the book’s detriment. In fact, the way the science is presented is confusing. Fluorides are brought up haphazardly and never fully explained. What are chemical differences between fluoride (the ionized molecule), fluorine (the element), fluoride salts (the compound found in toothpaste), calcium fluoride (naturally found in water) and fluosilicic acid (the waste product often added to fluoridate water)? Given the science we have on fluoride’s neurotoxic effects, could it play a role in the autism epidemic? How does this relate to ADHD, Alzheimer’s, MS – or any neurological disorder for that matter? Fluoride ions have an affinity for calcium in bones, how does fluoridation relate to osteoporosis? The audience desperately needs these type of answers but we never get them.
What we need is a more nuanced dialogue about the role of fluoride in the body, not less. Bryson should have embraced the controversy a bit more here and explained these different avenues of thinking instead of simply leaving the science of his opposition out of the text. It severely detracts from what this book could be.
Fluoride science has evolved further since this work was published back in 2006. There are now epidemiological studies examining the role of fluoride and bone fractures, with mixed results in low exposures (like the 1ppm rates CDC aims for in US public water system fluoridation) but more conclusive, damaging results in slightly high 2-4ppm window [5]. It’s still unknown which ethic groups could be most at risk from bone fractures though. More disturbing has been the development of studies that confirm fluoride (along with arsenic) has serious effects on the brain [6, 7, 8], lowering IQ in SE asian children. Again, these effects are seen in the higher 2-4ppm samples of fluoride, rather than the 1ppm exposures most Americans are seeing, but any time a substance causes neurological damage further study should be considered mandatory.
Advancing from this epidemiological base, one Chinese study group has recently isolated fluoride’s neurotoxic target as the hippocampus in the brain [9, 10], giving future researchers a tangible ‘fluoride pathogenesis’ to work with here. The hippocampus governs many of the higher cerebral functions of humans like memory storage and spatial orientation; any damage to it could cause a number of different, severe neurological issues – similar to the epidemiological observations showing impacts to IQ from SE Asia.
Even before this new evidence was published, the EPA and the National Academy of Sciences have been reexamining the data surrounding water fluoridation since 2006 . The EPA sets a maximum contaminant level (MCL) and a secondary maximum contaminant level (SMCL) for all water contaminants; effectively the MCL is the ceiling and SMCL is the least amount allowed. For fluoride that range has long been 2-4 mg/L in drinking water but the National Academy agreed that skeletal issues were found from fluoride exposures at levels as low as 1.5 mg/L, nearing the CDC’s water fluoridation targets of 1ppm.
*We would like to note that 1ppm is equivalent to 1mg/L and they are often used interchangeably in the research. It should also be noted the National Academy mentioned they choose not to examine fluoridation’s effects at .7 – 1.2 mg/L – the CDC’s target range – for reasons that go unmentioned but could easily be implied. Further, all figures here are per liter fluoride exposures that downplay the actual fluoride exposures many people will be exposed if they follow the Institute of Medicine’s (IOM) 3.7L/day water intake recommendation. Taken together, the average CDC fluoridated water range exposure (.95mg/L) multiplied by IOM’s average daily water intake (3.7L) would give the average American 3.515 mg worth of daily fluoride exposure – a figure that falls in the National Academy’s range for concern for skeletal problems and the recent IQ-reducing fluoride exposures from the Chinese study group mentioned above.
Moving Through the Fog
We gave you an overview of science surrounding fluoride here because it is complex – and evolving – but the fact Bryson remained silent on the matter, only pounding the conspiratorial angles of this drama, strikes us as foolish. While that makes for a juicy read, storming Alcoa for reparations will not help well-meaning scientists establish fluoride’s true toxicity. Echoing Bryson’s sentiments, we do agree that the industry connections are important to understanding the depths of this story. The fact CDC, FDA and ADA all remain in lockstep behind water fluoridation, even in the face of this new science, is disturbing. And for all we know, the avoidance of fluoride science could have been an editorial decision on his part or his publishing company but, with such charged subject matter, that was an exceedingly poor choice. We just wish he had done more to further the conversation, just as we wished Food Inc. had extended the sustainable agriculture dialogue in a meaningful way (it did not).
You could easily question Bryson’s objectivity when you read the book but you shouldn’t. Large passages pull from Bryson’s muckraking journalism background and you can almost feel the resentment he has towards those that have fluoridated our water. But he keeps himself in check very well. This stance creates a tone that is both a strength and weakness for Bryson. If you gravitate towards social justice issues, you will soak up this book’s charged approach; the more scientifically minded amongst you might find his angles off putting and his lack of science infuriating. We were somewhere in the middle, we found ourselves enjoying his style but longing for a more exhaustive scientific review somewhere in the text.
In general, Bryson does a masterful job of weaving political intrigue into an exceedingly readable text considering the subject matter. He creates a story with genuine heroes and villains you may find yourself thinking about long after you put the title down. Experts will surely find fault with Bryson’s work, especially on the scientific front, but if your only exposure to fluoride is the cursory knowledge of its presence in your toothpaste or water, you would be wise to visit this text. We recommend it.
Additional Resources:
CDC’s List of New Fluoridated Water Supply Communities (aiming for 75% coverage by 2010):
Environmentally speaking, eating meat is an awful thing to do. Whether is beef, pork, chicken or fish, meat is costly to our natural world to produce. Forests must be plowed into fields for grazing, even more food must be grown to feed the beasts, which produce more agricultural waste and, by and large, it’s a horribly destructive process. Fish would be a great alternative, if we hadn’t already overfished somewhere around 70% of the world’s fisheries, and farmed fish didn’t produce many of the same issues as farmed cattle or chickens, including runoff and habitat destruction. To me, the ecological impacts of meat consumption are the best argument I’ve ever heard for becoming a vegetarian or vegan.
It would be great if we could just stop eating meat all together. But there’s one problem – we need complete dietary protein, and about 60 grams a day of it. This is what I call the Protein Problem: the problem is that we need a lot of protein, nutritionally speaking, but producing it is an ecological nightmare. If you’ve read my post about why protein is so nutritionally important, you know that meat is simply the best source of complete dietary protein. But it’s not the only source of it, and many human herbivores instead choose to eat soybean products, for they are rare in the vegetable kingdom in that they, too, contain all the essential amino acids that people need in their daily diet. Tofu and other soy products have been around for centuries, but lately they’ve become more and more popular as people seek an ecologically friendly way of eating a balanced diet.
But is becoming vegetarian and eating tofu the solution to our protein problem? Unfortunately, it’s not that simple.
Brief History of Soy
Soybeans – a common crop
The soybean (or soya bean) is a species of legume, which places it in the same family as many pod-forming vegetables like peas as well as beans and lentils. Worldwide, over 150 million acres are planted every year. In the US, soybean oil accounts for about 80% of all the vegetable oils and animal fats (including things like butter) consumed each year. Due to it’s high production rate, it’s also often targeted for genetic engineering, and almost 90% of the 70 some odd million acres of US soybeans last year were genetically modified. Despite the large numbers, very little of the yearly soy crop is actually eaten by people. Most of it has its oils removed for use in industrial settings, the leftovers of which are used as animal feed.
People have been planting soybeans for over 5,000 years, but not to eat – like other legumes, soya plants fix nitrogen in the soil, making fields more fertile for other crops. It wasn’t until people started fermenting soy somewhere around 2,000 years ago that people began eating it, and even then it’s not been a huge part of the Asian diet. It only accounts for about 1% of the protein in their diet – the rest, go figure, is almost entirely from fish.
Soybeans are made into soymilk (which can be made into tofu), soy sauce, miso and oil. The beans are nutritious, though they cannot be eaten raw, for they contain enzymes that need to be deactivated by wet heat, as well as a host of compounds that aren’t terribly good for you. There is even some debate as to how much of this bad stuff goes away even when they’re fermented or cooked – just to warn you. But they can be up to 1/3 protein by weight, including all of the essential amino acids, as well as low in fat and high in other vitamins.
Most often, those who eat soy products as a dietary source of protein consume soymilk or its derivative, tofu. Soymilk is produced by soaking dry soybeans and grinding them with water. Tofu, in turn, is made from soymilk like cheese is from milk, by coagulating the protein into curd. Both contain much less protein than the beans did originally, though soymilk is comparable to cow’s milk while tofu contains only about 1/2 the amount of protein as cheese, though it also contains significantly fewer calories. Unlike the animal products they resemble, soymilk and tofu are naturally deficient in calcium, though often this nutrient is added during processing.
Soy’s Environmental Footprint
Soy products are often touted as natural alternatives to meat, but they’re far from it. Many are genetically modified, coated with herbicides and pesticides, and harvested with heavy machinery. Once taken from the land, the soybeans are processed in high-temperature factories and shipped thousands of gas-guzzling miles to end up on supermarket shelves. It would be funny that they’re called “natural,” if it wasn’t just so darned depressing to know the truth.
When you understand soy, beef starts to look better
Soy isn’t some miracle food that somehow helps out the planet while we eat it. Like any other plant, soybeans have to be cultivated agriculturally. This takes space and water, and means it will have an environmental cost no matter what. The impact of growing soy, in particular, has been devastating to the world’s natural resources.
Soy is native to Asia, but most of it isn’t grown there – it’s grown in the Americas. Why does that matter? It matters because when a plant is grown in an environment that it’s not native to, it can cause all kinds of problems. Because they are predominately grown in foreign soils, soybeans are one of the most disease-riddled crops out there. To combat this, soya farmers coat their fields in lots of pesticides and herbicides, and similarly soya has become one of the most genetically engineered crops in the world.
Unlike potentially environmentally friendly alterations that can be made (like making a plant drought-resistant so less water is used, or flood resistant so that weeds can be removed by flooding instead of chemicals), soy is most often engineered to resist herbicides so that more chemicals can be sprayed on them to combat other weeds. The end result of which, of course, is that more toxins are being used to produce soy than any other cash crop, with the exception of corn. Indeed, soy products are some of the most pesticide-contaminated foodstuffs in the world – even the organic soy (remember, organic doesn’t mean chemical-free).
In South America, soy farming is one of the worst things ecologically that has ever happened to the continent. Up until the early ’80s, more than 90% of the world export of soy came from the US. Latin and Southern America realized that they were missing out on a big opportunity, and began wide-scale soya plantation. By 2003, the combined exports from Central and South America exceeded that of the US. But where did they find the space to plant all these beans?
Soy plantations = goodbye rainforest
Well, it turns out that as soybeans caught on as a cash crop, farmers decided that soy fields were far more beneficial to them than rainforests. The result was massive deforestation, particularly of the Amazon Rainforest. In just one year, over one million hectares of Brazilian Amazon Rainforest was replaced with soya farms. Deforestation doesn’t just reduce ecological habitat for the thousands of endemic species that live there, it releases tons of carbon dioxide into the atmosphere, exacerbating climate change.
Furthermore, the loss of trees means less organisms helping fight global warming by using and storing CO2 in their tissues. On the plus side, activist organizations like Greenpeace have done a lot by exposing the atrocity that was occurring. They actually managed to push through a moratorium in 2008 that prevents any forest that is cleared from being used to grow soy. While this is a huge win for conservation, it doesn’t replace the millions of hectares of rainforest lost already, nor does it help the rainforest deal with the pesticides and nutrients that run off of these neighboring farms. Sadly, the moratorium is only a temporary solution to a very permanent problem.
The real question is, of course, is it better ecologically to eat soy than meat? After all, no matter how bad soy is for the environment, what people really want to know is whether it’s the lesser of two evils.
So What Diet Is Best for the Environment?
Unfortunately, the answer to that is muddy. Hands down, vegetarian diets are more efficient when it comes to acreage of land required to produce them… but that’s not the whole story. It does take less land area to produce soy than to produce cattle, chickens or pigs, so, yes, soy is better for the environment when it comes to square footage.
But quality is as important as quantity; a study from Cornell University suggests that completely cutting out meat might not be the best solution because animals like cattle can survive on land that isn’t suitable for crops, meaning poorer quality land can be used to produce livestock. In areas with poor-to-mediocre soil, for example, it’s probably more efficient to farm eggs for protein than to try growing vegetables that don’t flourish there – after all, animals can consume low-quality grain that isn’t necessarily fit for us. A recent study from the World Wildlife Fund also found that switching all of Britain’s meat eaters to tofu-eaters would require moreland to be farmed in the country because of this effect.
The hot debate, however, is which produces more carbon emissions: a vegan or meat-eating diet. Despite what you might expect, the results are actually quite mixed, and it largely depends on what you eat and where it comes from.
Food sustainability often depends upon its location, thanks Andrew Ciscel on flickr
One study estimated that it takes about 14 calories of fossil-fuel energy to produce one calorie of milk protein on a conventional farm and a little less than 10 calories of fossil-fuel energy for an organic farm. To produce the same amount of organic soy protein takes only 0.75 calories – which seems like an easy win. But there’s a problem with the comparison: we don’t eat raw soy protein. The processing of soybeans into a consumable form, like soymilk, takes a lot of energy. Some research has even suggested that the carbon footprint of cow’s milk is less than soymilk, as the process of turning soybeans into milk is actually quite energetically expensive (not to mention making soy-burgers) – but exactly how much of a carbon impact this processing has hasn’t been thoroughly researched yet.
As it stands right now, because soy products are only a small share of the market, they are only produced in a small number of areas and often have to be shipped large distances to reach their market. Exactly how important these food miles are to a foodstuffs ecological impact isn’t well understood, but they certainly don’t make it smaller. Obviously, travel increases carbon emissions, but there are many other consequences of long-distance migration of food that are often forgotten; the ecological cost of creating roads to access remote fields, for example, which damage even fairly untouched ecosystems in the area by creating more vulnerable ecological “edges”.
In the end, the science does seem to support that soy products are better for the environment than red meat- but only barely. And choosing sustainable seafood may be better than either one of them. Even if soy wins out against all the other protein options, it’s hardly the clear-cut ecological solution it’s made out to be. Furthermore, it may not be all that healthy to eat soy as your #1 source of protein in the first place. Soy contains hormone mimics, protein-degrading enzymes and other potentially toxic or carcinogenic substances whose effects have yet to be fully evaluated in people who completely replace meat with soy.
Being Nutritionally & Ecologically Balanced
I’m sure the debate will continue to rage on, but there are some things you can do to be more eco-friendly no matter what side you’re on.
First off, eat local, no matter what it is. Transportation of foodstuffs from one place to another is an ecological cost that we can lessen greatly. If you can get vegetables grown locally from a farmer’s market or beef from a farm down the road – great. If soy is grown and processed in your area – super! Whatever is produced within a few hundred miles of you is automatically the more ecologically responsible option, and often local, smaller farms have more sustainable practices, too. It makes it much easier to do this if you plan your meals around what’s in season in your area, so you are less tempted to grab your favorite veggies when they have to be imported from fairer climates.
Secondly, know where your protein comes from even if it isn’t local, and make the best decision you can as to which ones to pick. Places like the Monterray Bay Aquarium have made it easy to choose sustainable seafood options, and you can often buy chicken and beef from somewhat local farms, even at supermarkets. If you can’t go local, go grass fed – the label requires sustainable farming practices. If you crave red meat and live in the US, maybe try bison instead of beef. Bison is lower in fat, higher in protein, and more ecologically sustainable. The prairie grasses that bison are fed on have evolved along with the bison for centuries, and both benefit from the relationship.
And thirdly, eat less all together! While a lack of protein might be a problem in developing nations, in wealthy nations like the US, we tend to eat more animal protein than we need. Heck, we tend to eat more than we need, period – that’s why upwards of 1/3 of our population is obese. Start by eating smaller meals altogether, and if you’re really hungry, have a locally-grown fruit or something as a snack. That way you can improve your diet AND help the environment at the same time!
. His work paints a picture with enough intrigue to be nominated for an Oscar but remains deftly aware of itself long enough to stay away from hyperbole – most of the time at least.
