Understanding Our Bodies: Leptin (The Fullness Hormone)

Time and time again, I tell you guys that the best way to stay healthy is to stay informed. Read labels, I say. Know what you’re eating. Know what you’re not eating. Know this, know that, etc and make informed decisions. Well, part of making informed decisions is understanding how your body works. And for that reason, I’ve decided to dive into a bit of physiology.

Even informed consumers tend to know very little about how their appetites actually work. What makes you hungry or full? Why do some foods fill us up more than others? What exactly is going on in our bodies, anyway?

I figured you just might want to know. So here is part one of a new series I call “Understanding Our Bodies” – nutrition based on how our bodies work. And to kick it off is a little explanation of the fullness hormone: Leptin.

What is Leptin?

Leptin is a hormone that is tied closely to regulating energy intake and expenditure, including appetite, metabolism and hunger. It is the single most important hormone when it comes to understanding why we feel hungry or full. When present in high levels, it signals to our brain that we’re full and can stop eating. When low, we feel hungry and crave food. It does this by stimulating receptors in our hypothalamus, the part of our brains which regulates the hormone system in our bodies. When leptin binds to receptors in this part of our brains, it stimulates the release of appetite-suppressing chemicals. People with leptin disorders eat uncontrollably.

Leptin is high when you are full, low when you are hungry

Your leptin LEVEL is high when you are full, low when you are hungry

Now here’s the strange part.  Leptin is produced mostly by our adipose tissue – aka our fat.  The level of circulating leptin is directly proportional to the total amount of fat in the body.  That means the more fat you have, the greater the amount of leptin you have. It may seem counter-intuitive, but it makes sense in the end when we consider how yo-yo dieting tends to be. It takes some time for your body to adjust to large changes in body fat levels when it comes to leptin.

The total AMOUNT of leptin you have is related to your weight

The total AMOUNT of leptin you have is related to your weight

So when you lose a lot of weight quick, via liposuction or serious calorie restriction, your leptin levels plummet. Subsequently, you get hungrier, your thyroid decreases output and your metabolic rate drops. Your body then increases catabolic hormone activity and appetite, making you tend to slip off your regime and gain all that weight right back. That’s why crash diets are often ineffective – your leptin won’t let you eat less, and even if you do, you’re lethargic and your metabolic rate slows way down.

Of course, just because it makes things difficult for dieting, leptin levels are far more sensitive to starvation than overeating. So when you cut caloires and start ot burn fat, the leptin levels in your body plummet, but when you eat too much they don’t skyrocket – although they do increase. Leptin levels increase with increased insulin levels, like right after eat, and when our body is storing energy. Keeping this in mind, in general, can help you eat healthier and loser weight in the long run.

The Science of Leptin

Obviously, since leptin is so key to hunger and feeling full, scientists have been looking into it as a possible target for anti-obesity or weight loss. As it turns out, leptin controls a lot more than just our feelings of fullness.

Turning on leptin in the brains of mice causes them to exercise more, according to research from Harvard Medical School. It’s interwoven into how our bodies control our metabolism, activity levels, and energy budgeting – like immediately increasing appetite when fasting. While levels drop quickly, eating can bring them back up, too. It has been shown to reduce lipids in muscle and other tissues which lead to insulin resistance (the first step towards type 2 diabetes). It even controls what foods we find appealing when we’re just looking at them. Basically, it seems like the perfect way to lose weight – just give people more leptin,  right?  Well, there is another factor at work.

Leptin Resistance

But when researchers gave people leptin in human clinical trials, people didn’t lose weight. The trouble is, your body constantly tries to adjust basal leptin levels. If there’s a lot of it all the time, like in obese and overweight people, the brain loses sensitivity. Mice can become leptin resistant after as few as 3 days of overfeeding – so it happens quickly in response to consistent high blood glucose levels.

When obese, your leptin LEVELS spike radically because you have higher leptin AMOUNTS in your body (causing leptin resistance in the brain)

When obese, your leptin LEVELS spike radically because you have higher leptin AMOUNTS in your body (causing leptin resistance in the brain)

When it does this, it takes more and more leptin before our bodies feel full. When we get fatter, our bodies produce more leptin, and we become resistant to it. So obese people actually have unusually high leptin levels, but are not responsive to it. Even when healthy people eat a much lower calorie diet for a little while,  levels decrease, and they feel hungrier and less energetic, even if they haven’t lost weight yet. To lose weight and keep it off, you have to give your body time to adjust to the new, lowered leptin level, so it sets that as “normal” and you feel full when you’re supposed to.

Yes, he is.

Yes, he is.

The bad news is that not just excess weight can lead to leptin resistance. A new study published in the American Journal of Physiology found that high fructose diets can induce leptin resistance. These sugars actually impair the leptin’s ability to cross the blood-brain barrier and reach the hypothalamus. So even when the leptin levels are high, not enough is reaching the brain to tell the body to stop eating.

How do you use this information to lose weight or keep healthy?

First things first: quit the crash diets. You aren’t going to do your body any favors by losing weight too quickly. If you are trying to lose weight, though, there’s one thing you can do to help your body out: cheat. Seriously.

When you cut calories dramatically, your body acts like its starving and your leptin levels plummet. You’ll be hungry and generally have lower energy levels and want to eat more. So, once a week or so, cheat. Really cheat. Have a nice, high-calorie meal.

Your body then senses the rush of fuel and boosts leptin levels, increasing your metablism and priming your body for fat loss. Cheating helps ease your body down to lower daily leptin levels without making it feel too starved. That way, as you lose the weight, your body adjusts and realizes that the reduced leptin levels are normal not starving. And you get to enjoy something delicious – come on, it’s a win-win!

A beautiful sockeye salmon

A beautiful sockeye salmon

Secondly, avoid too much sugar intake. High calorie loads aside, the sugars make your brain less sensitive to leptin, which causes you to eat more and pack on the pounds. Conversely, some foods have been shown to increase leptin activity and sensitivity. The biggest connection scientists have found is between Omega-3 Fatty Acids and leptin. That’s right – the ever remarkable fish just keep getting better and better.  Researchers found that a group of people who ate a high proportion of fish every day had lower leptin levels despite eating the same calorie loads and having the same body fat as their fish free cousins – suggesting that a fish-rich diet increased their bodies’ sensitivity to leptin.

There’s good news, too, for those that are already overweight and leptin resistant: it’s only temporary. Research has shown that reducing fat content in leptin-resistant, obese mice allowed them to regain leptin sensitivity. So even if you’re overweight and likely leptin resistant, you can improve on that state. Unlike type 2 diabetes and insulin resistance, which is very hard to reverse, leptin resistance is fairly correctable with a normal, healthy diet and exercise.

And lastly, there’s something really simple that everyone can do to keep their leptin levels high and keep cravings under control: sleep well. When you go to sleep, your leptin levels naturally rise – after all, you want to be sleeping, not snacking, so your body knows to cut down on your hunger while you’re resting. But if you cut your sleeping short, your body tries to adjust by making you hungry again. Research has found that shorter sleep periods (6 hours or less instead of 8) lower overall daily leptin levels, cause an increase in appetite, and even make people crave carbs and other fattening foods. So its important for your body to rest well to maintain its natural hormonal balance, allowing you to look and feel your best.

In summary:

  • Stop crash diets
  • Eat ONE large meal per week to spark leptin-based weight loss
  • Avoid processed sugar
  • Eat Omega-3 (in fish/flaxseed/walnuts)
  • Sleep well

Like any other system in our bodies, the our hormonal appetite controls are sensitive to our daily habits and routines. The better a routine you have – sleeping well, eating right, and exercising, the more balanced your system will be and the better you will feel.

Stay tuned for more deep dives into the physiology of nutrition with the next installment of Understanding Our Bodies!

References:

  1. Williams, K., Scott, M., & Elmquist, J. (2009). From observation to experimentation: leptin action in the mediobasal hypothalamus American Journal of Clinical Nutrition, 89 (3), 985-990 DOI: 10.3945/ajcn.2008.26788D
  2. Havel, P. (2007). Role of adipose tissue in body-weight regulation: mechanisms regulating leptin production and energy balance Proceedings of the Nutrition Society, 59 (03) DOI: 10.1017/S0029665100000410
  3. Huo, L., Gamber, K., Greeley, S., Silva, J., Huntoon, N., Leng, X., & Bjørbæk, C. (2009). Leptin-Dependent Control of Glucose Balance and Locomotor Activity by POMC Neurons Cell Metabolism, 9 (6), 537-547 DOI: 10.1016/j.cmet.2009.05.003
  4. Pratley RE, Nicolson M, Bogardus C, & Ravussin E (1997). Plasma leptin responses to fasting in Pima Indians. The American journal of physiology, 273 (3 Pt 1) PMID: 9316457
  5. Chin-Chance C, Polonsky KS, & Schoeller DA (2000). Twenty-four-hour leptin levels respond to cumulative short-term energy imbalance and predict subsequent intake. The Journal of clinical endocrinology and metabolism, 85 (8), 2685-91 PMID: 10946866
  6. Enriori, P., Evans, A., Sinnayah, P., Jobst, E., Tonelli-Lemos, L., Billes, S., Glavas, M., Grayson, B., Perello, M., & Nillni, E. (2007). Diet-Induced Obesity Causes Severe but Reversible Leptin Resistance in Arcuate Melanocortin Neurons Cell Metabolism, 5 (3), 181-194 DOI: 10.1016/j.cmet.2007.02.004
  7. Zelissen, P., Stenlof, K., Lean, M., Fogteloo, J., Keulen, E., Wilding, J., Finer, N., Rossner, S., Lawrence, E., Fletcher, C., McCamish, M., & , . (2005). Effect of three treatment schedules of recombinant methionyl human leptin on body weight in obese adults: a randomized, placebo-controlled trial Diabetes, Obesity and Metabolism, 7 (6), 755-761 DOI: 10.1111/j.1463-1326.2005.00468.x
  8. Wang, J., Obici, S., Morgan, K., Barzilai, N., Feng, Z., & Rossetti, L. (2001). Overfeeding Rapidly Induces Leptin and Insulin Resistance Diabetes, 50 (12), 2786-2791 DOI: 10.2337/diabetes.50.12.2786
  9. Keim NL, Stern JS, & Havel PJ (1998). Relation between circulating leptin concentrations and appetite during a prolonged, moderate energy deficit in women. The American journal of clinical nutrition, 68 (4), 794-801 PMID: 9771856
  10. Shapiro A, Mu W, Roncal C, Cheng KY, Johnson RJ, & Scarpace PJ (2008). Fructose-induced leptin resistance exacerbates weight gain in response to subsequent high-fat feeding. American journal of physiology. Regulatory, integrative and comparative physiology, 295 (5) PMID: 18703413
  11. Peyron-Caso E, Taverna M, Guerre-Millo M, Véronèse A, Pacher N, Slama G, & Rizkalla SW (2002). Dietary (n-3) polyunsaturated fatty acids up-regulate plasma leptin in insulin-resistant rats. The Journal of nutrition, 132 (8), 2235-40 PMID: 12163668
  12. Winnicki M, Somers VK, Accurso V, Phillips BG, Puato M, Palatini P, & Pauletto P (2002). Fish-rich diet, leptin, and body mass. Circulation, 106 (3), 289-91 PMID: 12119240
  13. Enriori, P., Evans, A., Sinnayah, P., Jobst, E., Tonelli-Lemos, L., Billes, S., Glavas, M., Grayson, B., Perello, M., & Nillni, E. (2007). Diet-Induced Obesity Causes Severe but Reversible Leptin Resistance in Arcuate Melanocortin Neurons Cell Metabolism, 5 (3), 181-194 DOI: 10.1016/j.cmet.2007.02.004
  14. Nedeltcheva AV, Kilkus JM, Imperial J, Kasza K, Schoeller DA, & Penev PD (2009). Sleep curtailment is accompanied by increased intake of calories from snacks. The American journal of clinical nutrition, 89 (1), 126-33 PMID: 19056602
  15. Taheri, S., Lin, L., Austin, D., Young, T., & Mignot, E. (2004). Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index PLoS Medicine, 1 (3) DOI: 10.1371/journal.pmed.0010062
  • Mimi Serrao

    Very good information. And completely on target. Crash diets are useless and a long, slow weight loss with improved quality of food intake works so much better. I know, I’ve been down both paths, and slow and steady is the answer.

    Thanks for your good articles.

  • Mimi Serrao

    Very good information. And completely on target. Crash diets are useless and a long, slow weight loss with improved quality of food intake works so much better. I know, I’ve been down both paths, and slow and steady is the answer.

    Thanks for your good articles.

  • Laurie Ulrop

    Thanks for such an information packed artilce. I just discovered this website and was really taken by the indepth coverage and research done on these articles. This article fit into what I was researching myself and wanted you to be aware of some additional info you might find interesting for a follow-up article. Check out Life Extension.com and their artilces about Leptin and the supplement *Integra-Lean Irvingia.
    Interesting stuf!! Thanks!

  • Laurie Ulrop

    Thanks for such an information packed artilce. I just discovered this website and was really taken by the indepth coverage and research done on these articles. This article fit into what I was researching myself and wanted you to be aware of some additional info you might find interesting for a follow-up article. Check out Life Extension.com and their artilces about Leptin and the supplement *Integra-Lean Irvingia.
    Interesting stuf!! Thanks!

  • http://www.antioxidants-for-health-and-longevity.com stan mrak

    Regarding the hypothalamus gland mentioned here: I have read something about how food additives such as aspartame and msg (which is in almost all processed foods) damage the functionality of this gland, which can lead to weight problems. Pregnant women may even pass on a tendency in their babies to grow up with obesity problems from consuming these additives.

  • http://www.antioxidants-for-health-and-longevity.com stan mrak

    Regarding the hypothalamus gland mentioned here: I have read something about how food additives such as aspartame and msg (which is in almost all processed foods) damage the functionality of this gland, which can lead to weight problems. Pregnant women may even pass on a tendency in their babies to grow up with obesity problems from consuming these additives.

  • http://www.wooten57.com debbie

    My question to you is does this effect your FT3 levels? For myself I have tried everything under the sun! Synthroid, Armour, Cytomel, hormone treatment as in estrogen and progesterone. I am a Thyroid Cancer survivor I have never been the same since radiation and removal of my Thyroid my FT3 is at .99 something is stoping it from raising even straight Cytomel lowered my FT3 thirty points. How does this happen if my cortisol is fine?

  • http://www.wooten57.com debbie

    My question to you is does this effect your FT3 levels? For myself I have tried everything under the sun! Synthroid, Armour, Cytomel, hormone treatment as in estrogen and progesterone. I am a Thyroid Cancer survivor I have never been the same since radiation and removal of my Thyroid my FT3 is at .99 something is stoping it from raising even straight Cytomel lowered my FT3 thirty points. How does this happen if my cortisol is fine?

  • Joanna

    When you say ‘hunger’, are you referring to actual physical hunger, or cravings, or both?

  • Joanna

    When you say ‘hunger’, are you referring to actual physical hunger, or cravings, or both?

  • Ricki Altenburg

    I am not overweight and never have been, but I just read a study that shows that higher leptin levels are linked with a decrease in alzheimer. So, I’m curious as to what normal levels should be, and if a thinner person is at higher risk of developing Alzheimer. Also, is it recommended for a thin person to take leptin as a supplement?

  • Ricki Altenburg

    I am not overweight and never have been, but I just read a study that shows that higher leptin levels are linked with a decrease in alzheimer. So, I’m curious as to what normal levels should be, and if a thinner person is at higher risk of developing Alzheimer. Also, is it recommended for a thin person to take leptin as a supplement?

  • Kristin

    Great article, but I have a question – how long does it takes for a body to adjust to a new body weight and corresponding leptin level? I’m a 130 lbs female. If I lose 4 lbs in a week (about 3% of my body weight – and yes, I realize “healthy weightloss” is only 1-2 lbs per week), will that drive my leptin levels up? If I am able to maintain this loss, when will my leptin balance itself?

    Thank you.

  • Kristin

    Great article, but I have a question – how long does it takes for a body to adjust to a new body weight and corresponding leptin level? I’m a 130 lbs female. If I lose 4 lbs in a week (about 3% of my body weight – and yes, I realize “healthy weightloss” is only 1-2 lbs per week), will that drive my leptin levels up? If I am able to maintain this loss, when will my leptin balance itself?

    Thank you.

  • http://www.wholehealth.com/vitamins-supplements/leptifit-leptin-enhancing-formula Leptin

    This is an informative article. I’d rather say that Leptin is very important to everybody, they must know their leptin levels, probably to avoid obesity, Obesity is a mere factor that causes cardiovascular problems, else is respiratory diseases. So we must observe what amount of food we must intake., foods that rich in Omega 3 which is good for the heart, satisfaction in every meal isn’t bad but enough is better for healthier lifestyle.

  • Jacob Cullin

    test

  • http://www.wholehealth.com/vitamins-supplements/opc-grape-seed-extract Grape Seed

    I agree drinking a leptin suplement while having a work out or any exercises is a fast way for us to loose weight,

  • http://www.wholehealth.com/vitamins-supplements/leptifit-leptin-enhancing-formula Leptin Supplement

    I agree drinking a leptin suplement while having a work out or any exercises is a fast way for us to loose weight,

    • http://twitter.com/BenBMCFitness Ben Chambers

      Leptin is a protein based hormone therefore comsuming it in a drink or pill would have no effect what so ever as it would just be digested. there was a study done whereby a group of people were split into 2 groups. Both groups had to follow the same exercise programme, 1 group was given leptin injections and the other was injected with a placebo. The group which were injected with the leptin all lost more weight. The reason being if you inject leptin it goes straight into the bloodstream then works its magic. However the problem with this is that leptin injections are very expensive

  • http://www.lipoguide.com/ Lipo

    Its right that drink leptin is good for during work out or any exercises. I only recommending that after any surgery, we need to extract control over foods and also control catabolic hormone activity.
    Lipo

  • Ann kwiat

    Very informative and interesting.

  • laura

    great article and very helpful for my research. Thanks :-)

  • Infant

    It gave me useful info

  • Wulfgar

    A little over 20 years ago I walked out of a McDonalds after eating for lunch a huge meal and still wanted more. I was about 27 at the time. I was and still am a mason/ construction worker and strong and in pretty good shape.6’2 175lbs in summer and about ten more during the winter for some reason… Hers the point; me, my boss and most of the crew loved McDonalds it was good and cheap and it was everywhere and I ate a meal like that almost day at lunch and stayed in good shape just doing my trade and very little exercise. That day when I was buying a quick cone as I was
    Heading out the door ha k to work I thought to myself I just ate all that food and here I’m buying an ic e cream and you do this all the time why is that? In a splinter of a minds eye the answer came back and it was; “there putting stuff I the food to make you eat more. That’s what God told me that day and over the last twenty I not only watchd myself get fat but almost the whole of America. I haven’t eaten at a McDonald’s since the Mary S. starvation tragady. And I vowed to God I wouldn’t eat fast food. I was shocked that this goes on all over America. With all this food. I never forgot that day but I didn’t know what it was in the food, and had no time to research, I didn’t get my first computer until ’97 and then new nothing about it. No one listened not even my closest confidant, my vife and family they said I was nuts and its always been here and everyone does it and yor stupid.there fat now and my 16 year old son is 300 lbs. he’s taller then me though but has diabetes. Anyways I’m now divorce. Needless to say this was one of the issues, but I was stupid. Well over the last three years if lost weight and I’m back down to 185. I stopped eating as many of the things I thought were bad and it just happened. I would also like to say I’m sorry for making fun of fat people. It’s not there fault. Imagine a chemically engineered substance that makes your body day! High fructose sugar. Conspiracy theory is now conspiracy fact.

    • Guadalupe Chapa

      Read a book called”CHEW ON THIS.” There is more to it than that.

  • Grace Kusta Nasralla

    This is the best article I have read so far on “increasing leptin sensitivity” in the body… Thank you for your educational approach :)

  • tish

    I do not eat fish, and do not like any type of nuts. Can I use a fish supplement?

  • Beth Mcguire

    if you want to know more about the uglies about fractose sugars in our grocery foods watch Sugars; The Bitter Truth – YouTube https://www.youtube.com/watch?v=dBnniua6-oM

  • Anonymous

    Also, avoid liposuction, no matter how minor the plastic surgeons try to tell you it is when you go in for a needed breast surgery.

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