One of the most confusing things when it comes to proper nutrition is the role of fats. We’re constantly told that fats are evil things which will expand our bellies to the size of hot air balloons. This constant anti-fat attitude is behind many of the popular diet trends, which focus on cutting fats and carbs and replacing them with proteins. But not all fats are the same, and not all of them are bad for you. In fact, many fats are very good for you. Recent research has found that the low-fat diet trend is simply wrong for us– we’re not supposed to have no fat in our diets. you just have to know which is which.
Because they’re called by their names more than their general category, you might not even know that the good fats are even fats at all. The fats that are good, in general, are ones that are cis-unsaturated. In chemistry, fats are carbon strings with hydrogens attached to them. “Unsaturated” means that the carbons are not bound to as many hydrogens as they can. So fats can be monounsaturated (only one hydrogen less than the possible maximum), polyunsaturated (2 or more less) or saturated. And of the unsaturated fats, there are two main forms: cis and trans. This has to do with how the carbons bond to each other where there is a hydrogen missing. In nature, they bond in what is called a ‘cis’ manner, which creates a bend in the molecule. When we artificially change monounsaturated fats into other fats, they instead form a ‘trans’ bond, which is almost straight.
Our bodies are naturally very good at breaking down and utilizing the cis-unsaturated fats. They fit better into the enzymes in our bodies which cut apart the carbons and chop up the molecules for use. That said, have you heard of cis-unsaturated fats? Probably not. They don’t appear on nutrition labels as a category, and are rarely referred to as such by the media.
What you might have heard of, though, are Omega Fatty Acids, Oleic Acid, Palmitoleic Acid and Linoleic Acid. These are all cis-unsaturated fats. The benefits of these kinds of fats are well explored by scientists. They contribute to lower cholesterol levels and reduced risk of heart disease. They’re connected with positive effects from intelligence to weight loss. In fact, eating them is better than cutting your fats period. Studies have shown that increased intake of these unsaturated fats, like in a Mediterranean diet which includes large amounts of olive oil (chock full of unsaturated fats), leads to all kinds of health benefits [1,2,3]. In general, they’re really, really good for you.
The foods that are highest in unsaturated fats include:
- nuts (like walnuts and pecans)
- vegetable oils (like canola oil, olive oil and grapeseed oil)
They’re found in animal products, too, but animals tend to have saturated fats as well as unsaturated ones. In general, the FDA recommends that no more than 30% of your overall calorie consumption comes from unsaturated fats, or 67 grams given a 2000 calorie diet.
The Bad (but not sooo bad)
Saturated fats are often touted as the bad guys. But they’re not quite as bad as they’re portrayed. These are seen as the main culprit behind high blood cholesterol and are known to raise bad LDL cholesterol levels. Unlike unsaturated fats, though, they don’t lower good HDL cholesterol levels.
Don’t write them off as terrible for you just yet. Unlike trans fats, saturated fats occur naturally in high concentrations, particularly in animals. Some studies have found that a little saturated fats actually increases the benefits of some unsaturated fats when eaten together . Still others have found that diets high in certain saturated fats from vegetables not animals, like unrefined, cold pressed coconut oil , might even be good for you [5,6]. Diets that are low-carb but high in protein and fat, for example, don’t automatically increase the risks of heart disease. Other studies have had mixed or even positive results from diets with saturated fats. One in 2007, for example, found that lower risk of heart disease was associated with increased fat intake so long as it wasn’t trans fat, including benefits from eating more saturated fat.
The key, it seems, is moderation, not complete extermination of saturated fats from our diets. The USDA and the Department of Health and Human Services say that up to 10% of your daily calorie intake can come from these fats, which are found in meat, cheese, dairy products and tropical oils like palm and coconut oil.
The worst fats for you, by a landslide, are the trans fats. While other dietary fats have redeeming qualities, trans fats seem to have none. They’re almost entirely man-made, created by adding hydrogens to other fats. This process, called hydrogenation, turns oils into the semi-solid margarine and other products that are associated with trans fats. These trans fats are useful because they have a longer shelf life, are hard enough to stay solid at room temperature, and yet can even be malleable cold. Unfortunately, there’s a cost for their benefits.
Trans fats, in general, are bad for you. They raise your risk of diabetes and heart failure, particularly by raising “bad cholesterol” levels in the body. But they don’t stop there. They not only raise LDL (bad cholesterol) levels, they lower HDL cholesterol levels – the good ones. In 2006, a scientific review of fats from the New England Journal of Medicine stated clearly that “from a nutritional standpoint, the consumption of trans fatty acids results in considerable potential harm but no apparent benefit.”
The damning evidence against trans fats comes from a study of 120,000 female nurses from 1976 to 1990. The Nurses’ Health Study found that the risk of coronary heart disease nearly doubled for every 2% increase in trans fat calories consumed instead of carbohydrates. Considering the same increase in risk takes a 15% increase in saturated fats and that eating the other unsaturated fats actually lowers heart disease risks, there seems to be no reason to eat trans fat at all. And if that weren’t bad enough, trans fats have also been linked to liver problems and even infertility.
Trans fats are the ones found in fried foods, commercial baked goods, shortening and margarine. Based on the source list, it’s not surprising it’s not healthy. The American Heart Association says that no more than 1% of your total daily calories should come from trans fats to maintain a healthy heart, and, in general, any increase in trans fats increases your risk of coronary heart disease and stroke.
How To Get The Good Without Too Much Bad Or Ugly
Now that you know what to look for, you can make more informed choices about your meals when you hit the grocery store. Read the nutrition labels carefully. For example, “no trans fat” can still contain up to 6% trans fat according to US guidelines, and ‘high’ or ‘low’ fat aren’t as important as the kind of fat. Just because something contains 10 g of fat doesn’t mean it’s awful for you – check and see if the fat is saturated or unsaturated.
The best way to keep your diet healthy is to do little things to replace your trans or saturated fats with cis-unsaturated ones. For example:
- cook with olive oil or sunflower oil instead of butter or margarine
- eat fish, which is high in Omega Fatty Acids but low in other kinds of fats
- grilling instead of frying your meat
- removing the skin from your chicken breast can reduce saturated fat levels by 30%-50%
Doing these type of things will decrease your risks of heart disease, obesity, diabetes, and a bunch of other diseases.
Before I get my head chopped off in the comments for saying fats are healthy, don’t get me wrong – most Americans already eat way more fat than we should, of any kind. So it’s not necessarily a bad thing to cut down your fat intake if you’re looking to make your diet a bit more nutritious. But if you already eat somewhat healthy, are at a normal weight and are just looking to improve yourself, cutting the fat out of your diet entirely isn’t the way to go. Ideally, even if you’re trying to lose weight and eat healthier from a less-than-healthy starting point, you shouldn’t see all fats as the enemy. My point is that fats really are good for you, in the right amounts.