“20 Healthy Fats to Make You Thin”1
“11 Best Healthy Fats for Your Body”2
These are headlines for articles that throw around names of “clickbait” foods. Grass-fed beef, coconut oil, ghee, and dark chocolate are just some examples of these fatty “superfoods.”
Not just the media but even professionals working in medicine, nutrition, dietetics, and other scientific fields love to generalize and label foods as “healthy fat” or “unhealthy fat” foods.
While the intention may be to make things simple and easier for the public to understand, instead we are often left confused.
Let’s look further into what we really mean when we use the phrases “healthy fat” or “unhealthy fat” or take extreme “low-fat” or “high-fat” views of what a healthy diet should look like.
Here are some common myths:
1. Low Fat Diets are the Healthiest Diets
Back in the 1940s, fat and cholesterol became the enemies. The first Dietary Guidelines for Americans, published in 1980, listed, “Avoid too much fat, saturated fat, and cholesterol” as the third guideline3.
It was not until the 2000s that we really began to see evidence that a low-fat diet is not as amazing as we once thought.
For instance, contrary to what many of us expected, a low-fat diet does not reduce risk of cardiovascular disease4. We now understand that low-fat diets are not better than any other diet and can even be dangerous5.
2. High Fat Diets are the Healthiest Diets
Since the evidence about low-fat diets came into light, the media did somewhat of a flip-flop, telling us that fat and cholesterol are not the enemies but rather beneficial for our health. The ketogenic diet, an extremely high-fat, low-carb diet, is gaining popularity among the general population, athletes, and celebrities.
Like low-fat diets, however, high-fat diets are not better than any other diets. A healthy diet is a varied diet, and a diet that helps us lose weight is simply one that is calorie-restricted (and that we can stick to), regardless of its fat content6.
3. There are Good Fats and Bad Fats
Although all types of fat supply us with the same amount of energy per gram, there are different types of fat. However, no type of fat is inherently bad. An excess of calories is bad. (An excess of anything is bad.)
Replacing saturated fat with polyunsaturated fat may be protective against cardiovascular disease7,8. This means that dose matters and that ratio matters. However, choosing to consume or not to consume a type of fat does not necessarily mean anything for our overall health.
Unsaturated fats are not heroes, and saturated fats are not villains. All fats provide us with energy that we need to live. We need to look at how much of a particular food is being consumed and what else is being consumed to determine the “goodness” or “badness” of a diet.
4. We Need to Avoid Saturated Fats
Simply decreasing saturated fat intake will probably not have any benefit. A 2017 advisory from the American Heart Association found that replacing saturated fat with polyunsaturated fat reduced the risk of heart disease by 30% and that replacing saturated fat with any unsaturated fat decreased levels of LDL cholesterol9.
This suggests that we should consume unsaturated fats in addition to saturated fats – not that we need to avoid saturated fats. Many foods high in unsaturated fats, like salmon, also contain saturated fat. If we avoid saturated fat, we put ourselves at risk of not getting enough other nutrients and perhaps getting too much of others.
Additionally, when we decrease saturated fat, we often increase added sugars. (Calories need to come from somewhere!) High-fat, high-sugar foods are not problematic on their own, but when we consume them in abundance, we get an overall dietary pattern that can lead to poor health outcomes.
5. We Need a Specific Ratio of Omega-6/Omega-3 Fatty Acids
The problem is really that diets in the US are typically low in omega-3 fatty acids. Much of our diet is corn, sugar, and animal fat10.
While diets with a high omega-6/omega-3 ratio like typical Western diets may promote the development of chronic diseases11, we do not need to worry about exact numbers. We just need to consume a balanced, varied diet.
We will get health benefits from intentionally increasing our omega-3 fatty acid intake or substituting foods that aren’t as nutrient-dense in our diet for foods that are high in omega-3 fatty acids, regardless of the specific ratio of omega-6 to omega-3 fats in our diet. Foods high in omega-3 fats include fish, flaxseeds, walnuts, canola oil, and soybean oil.
6. Fat Keeps You Full
Fats are satiating, but they are also the most calorie-dense nutrient. This means that servings of high-fat foods are often small. Just think about how small servings of nuts, nut butter, and oil are.
Additionally, we also lack signaling molecules for fat that we have for protein and carbohydrates. Feeling full is influenced by many factors, like water, fiber, and air content of foods.
While all types of fat offer us the same amount of energy per gram, different types of fat affect our bodies in different ways. As a population, we need to consume more unsaturated fats, especially omega-3 fats (a type of polyunsaturated fat).
Monounsaturated fats are found in high concentrations in avocados, nuts, seeds, and olive, peanut, and canola oils. Polyunsaturated fats are found in high concentrations in fish, walnuts, flaxseeds, and sunflower, corn, soybean, and flaxseed oils. Cutting back on saturated fats is probably not helpful unless unsaturated fat intake is simultaneously increased.
A healthy diet is one that has some of each type of fat. There is no reason to avoid dietary fat (except for artificial trans fats, which can have harmful health effects). At the end of the day, we’re much better off focusing on overall diet variety rather than single nutrients.
- 20 Healthy Fats to Make You Thin | Eat This Not That [Internet]. [cited 2018 Feb 10]. Available from: http://www.eatthis.com/healthy-fats/
- 11 Best Healthy Fats for Your Body [Internet]. Dr. Axe. [cited 2018 Feb 10]. Available from: https://draxe.com/healthy-fats/
- U.S. Department of Health and Human Services and U.S. Department of Agriculture. Nutrition and Your Health: Dietary Guidelines for Americans. 1st Edition. 1980. Available at https://health.gov/dietaryguidelines/1980thin.pdf
- Howard BV, Van Horn L, Hsia J, Manson JE, Stefanick ML, Wassertheil-Smoller S, Kuller LH, LaCroix AZ, Langer RD, Lasser NL, et al. Low-Fat Dietary Pattern and Risk of Cardiovascular Disease: The Women’s Health Initiative Randomized Controlled Dietary Modification Trial. JAMA. 2006;295:655.
- Burr GO, Burr MM. A new deficiency disease produced by the rigid exclusion of fat from the diet. J Biol Chem. 1929;82:345-367.
- Bellissimo N, Akhavan T. Effect of macronutrient composition on short-term food intake and weight loss. Adv Nutr. 2015;6:302S–8S.
- Hooper L, Martin N, Abdelhamid A, Davey Smith G. Reduction in saturated fat intake for cardiovascular disease. Cochrane Database Syst Rev. 2015;CD011737.
- Mozaffarian D, Micha R, Wallace S. Effects on Coronary Heart Disease of Increasing Polyunsaturated Fat in Place of Saturated Fat: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. PLOS Medicine. 2010;7:e1000252.
- Sacks FM, Lichtenstein AH, Wu JHY, Appel LJ, Creager MA, Kris-Etherton PM, Miller M, Rimm EB, Rudel LL, Robinson JG, et al. Dietary Fats and Cardiovascular Disease: A Presidential Advisory From the American Heart Association. Circulation. 2017;CIR.0000000000000510.
- Turner BL, Maes K, Sweeney JL, Armelagos, GJ. Human Evolution, Diet and Nutrition: Where the Body Meets the Buffet. In New Perspectives in Evolutionary Medicine. Oxford: Oxford University Press, 2008:55-71.
- Simopoulos AP. The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother. 2002;56:365–79.