Let’s Talk Fats

What are fats?

Fats are a subcategory of a broader macronutrient called lipids. All fats are lipids, but not all lipids are fats. Lipids at large have a multitude of functions, including cell structure and signalling, immune support, hormone regulation, insulation, and absorption of vitamins A, D, E, and K, but fats in particular play an important role in our body’s energy supply. When you eat fat, it gets broken down into triglycerides, some of which will be used for immediate energy, while the rest will be stored for later in adipose tissue, or body fat. Between meals, your body pulls from those energy stores to supply itself with the fuel it needs to get through to your next meal.

Beyond energy, certain types of fats provide significant health benefits, especially cardiovascular-related ones. But not all fats are created equal, and there’s a definite hierarchy: unsaturated fat holds first place, saturated fat ranks second, and trans fat is dead last.

Unsaturated fat

Often referred to as “healthy fat,” unsaturated fat raises levels of “good” cholesterol (high-density lipoprotein, or HDL), lowers levels of “bad” cholesterol (low-density lipoprotein, or LDL), improves heart health, and has anti-inflammatory properties (Moll, 2023).

There are two types of unsaturated fat: monounsaturated and polyunsaturated. The distinction lies in their molecular structures—monounsaturated fat has one double bond in its carbon structure, while polyunsaturated fat has two or more. Things like olives and olive oil, peanuts and peanut butter, pumpkin seeds, sesame seeds, avocados, and egg yolks all have high amounts of monounsaturated fat, while corn, soybean, and safflower oils, walnuts, flaxseeds, and fish are rich in polyunsaturated fat.

Neither monounsaturated nor polyunsaturated fat is necessarily better or worse for you than the other—both offer a wealth of nutritional value and should be the primary sources of fat in your diet.

Omega-3 and omega-6 fatty acids

Omega-3 and omega-6 fatty acids are types of polyunsaturated fat, and while most people already get enough omega-6 fatty acids, omega-3 intake often falls short.

Omega-3s are important for cellular structure and function, especially within your brain and eyes. They also promote heart health, ease inflammation, help with autoimmune conditions, may lower your risk of certain cancers, Alzheimer’s, and dementia, and the list goes on (Hjalmarsdottir, 2023). Fatty fish are the best sources of omega-3s—for example, salmon, mackerel, and herring—but you can also find them in plant-based foods such as walnuts, flaxseeds, and chia seeds. Fish oil supplements are also common to support omega-3 intake, but always talk to your doctor or dietitian before taking a supplement.

Omega-6 fatty acids sometimes get a bad rap, but in moderate amounts, studies have actually shown their heart-healthy effects, role in brain function and metabolism, support of the reproductive system, and contribution to hair, skin, and bone health (Lopez-Jimenez, 2023; “Omega-6 fatty acids,” n.d.). Sources of omega-6 fatty acids include sunflower and sesame seeds, corn and grapeseed oils, Brazil nuts, and almonds.

Both omega-3 and omega-6 fatty acids are essential, meaning our bodies can’t synthesize them and we need to get them from food or supplements. Adequate intake is best obtained via a diet rich in a variety of polyunsaturated fats, with additional emphasis placed on sources of omega-3s given their tendency to be underconsumed.

Saturated fat

Saturated fat—often viewed as a “sometimes fat”—is found in things like animal meat, dairy products, coconut oil, and palm oil. While saturated fat shouldn’t be the primary source of fat in your diet, it’s not necessarily harmful, like we’ve been led to believe, and claims linking saturated fat to heart disease in particular aren’t supported by evidence (Gershuni, 2018). The concern with saturated fat is that it raises LDL cholesterol, but research suggests that what actually matters more than maintaining low levels of LDL cholesterol in the prevention of heart disease is raising levels of HDL cholesterol (Perna & Hewlings, 2022). This same research also shows that those with high intakes of saturated fat tend to smoke, live sedentary lifestyles, and lack fibre, so it’s unclear whether elevated risk of heart disease is a result of saturated fat itself or these frequently coupled behaviours. In fact, full-fat dairy—specifically, yogurt, kefir, and cheese—may lower heart disease risk because of high nutrient bioavailability, or how effectively nutrients can be used by our bodies, and anti-inflammatory properties (Lordan et al., 2018).

Saturated fat is considered a “sometimes fat,” not because it’s inherently bad for you, but because unsaturated fat holds the highest nutritional rank in the realm of dietary fat, and should be prioritized over saturated fat. But there’s no need to buy 0% yogurt if you prefer higher-fat versions, butter’s totally fine—and potentially beneficial—in moderation, and long live the charcuterie board.

Trans fat

Let’s call this an “almost never” fat. Also known as partially hydrogenated oils, trans fats are made through a process called “hydrogenation,” wherein hydrogen is added to liquid vegetable oil to form a solid or near-solid (“Trans Fats,” 2017). Small amounts of trans fats exist naturally in some meat and dairy products and aren’t typically cause for concern in this regard, but artificial trans fats, or those made through hydrogenation, are extremely harmful.

Trans fats are added to some processed and commercially-made baked goods and fried foods to prolong shelf life and improve taste and texture, but not without some scary side effects. They raise LDL cholesterol, lower HDL cholesterol, and increase your risk of heart disease, diabetes, and stroke (“Trans Fats,” 2017). The World Health Organization suggests that a high intake of trans fats increases your risk of any cause mortality by 34% (2018).

Many countries have restrictions on partially hydrogenated oils in food manufacturing. Some countries, including Canada and the US, have actually banned trans fats, but they still find their way into some products in small amounts. It’s therefore important to be mindful of anything containing trans fats on the nutrition facts label or partially hydrogenated oils in the ingredients list and to consume trans fats in extreme moderation.

Recommended fat intake

The Acceptable Macronutrient Distribution Range, or the AMDR, recommends 20-35% of total daily calories come from fat, with saturated fat constituting no more than 10% of calories. Fat contains nine calories per gram, so based on a 2000-calorie diet, this equates to approximately 44-78 grams of fat per day, or 400-700 calories, with saturated fat constituting a maximum of 22 grams, or 200 calories.

The lower limit of the AMDR represents the amount of fat required to support overall energy intake, adequate consumption of fatty acids and fat-soluble vitamins, and an optimal LDL-to-HDL ratio (Liu et al., 2017). Going below the AMDR presents a slew of health risks, including micronutrient deficiencies, compromised hormone function, and negative effects on mental health (Gora, 2022). The upper limit intends to curb overconsumption of calories rather than of fat itself, and the limit on saturated fat encourages the prioritization of unsaturated fat (Liu et al., 2017).

Within the AMDR, the right amount of fat for you is the one that fits within the context of your other macros, allows you to remain within your daily calories, and suits your lifestyle, preferences, and goals. Fat might come secondary to other macros depending on these factors, but this by no means implies that fat isn’t important—you just might tailor your fat intake around your calories and other macros, protein in particular, rather than the other way around.

Fats and weight loss

First things first, eating fat doesn’t lead to additional body fat—excess calories do. If you eat butter, avocados, bacon, or nuts, for example, you won’t inherently gain weight simply because those foods contain high amounts of fat. You will, however, gain weight if you’re consistently eating 2500 calories and your body’s only burning 2000, regardless of whether those calories come from fat or elsewhere.

Similarly, eating less fat doesn’t automatically elicit weight loss—a calorie deficit does. If minimizing your fat intake helps you achieve a calorie deficit, then low-fat can indeed support weight loss, but it’s not necessarily a worthwhile or recommended approach. Low-fat isn’t any more effective for weight loss than other means of reaching a calorie deficit, such as portion control, and given their satiating effects, you’re actually better off incorporating fats to support weight loss rather than restricting them (Kim, 2021). Also, as discussed in my post All Foods Fit: Ditching Restrictive Diets, restriction tends to backfire, and the best approach to weight loss is the one that makes room for all of the foods you enjoy in moderation. Think about portion size rather than elimination—if you’re cooking with olive oil, for example, consider how much you’re using but not whether to use it at all.

It’s also important to not let weight loss or any body composition goals override your fundamental nutrition needs. Fats indeed carry a higher caloric load, but they have an essential purpose alongside those calories, and food is so much more than calories alone. It’s vital to be in a calorie deficit for weight loss, but a calorie deficit and adequate fat intake can coexist.

Fats and muscle growth

The valuable contribution of fat in the process of muscle growth shouldn’t be overlooked. Fat doesn’t directly build muscle, but it is involved in a lot of the processes that do—for example, fats aid in injury recovery, including muscle trauma brought upon by resistance training (Kunik, 2022). They also help to regulate testosterone, an important element of muscle growth, and facilitate the absorption of vitamins A, D, E, and K, all of which support hypertrophy and muscle function in some capacity (Kunik, 2022).

If your goal is muscle growth, it’s important to consider when you’re eating fat. Without getting too far into the complexities of nutrient timing, fats take a long time to be converted into usable energy and aren’t the most effective pre-workout fuel compared to carbs and protein. In terms of incorporating fats into post-workout nutrition, some believe that because fat slows digestion and absorption of protein and carbs, it should be avoided after training to maximize muscle protein synthesis. On the other hand, some research suggests that this effect isn’t significant or that fat may actually support post-workout recovery (Semeco, 2023). All that to say, it’s likely okay to eat some fat pre- and post-workout, but it’s best to obtain the majority of your fat intake outside of this window.

Fats and endurance

Exercise is largely powered by fat when intensity is low to moderate and duration is long—i.e., endurance exercise. This includes things like walking, jogging, cycling, and swimming when performed at lower intensities for longer periods of time. Even when exercise intensity is higher and carbs are the main fuel source, your body still needs fat in order to access those glycogen stores (Quinn, 2023). Additionally, there’s evidence to suggest that regularly obtaining adequate dietary fat can actually help your body prioritize fat for fuel, which improves VO2max and exercise performance (Pendergast et al., 1996; Hetlelid et al., 2015).

Fats are also important for endurance exercise as they help to minimize the risk of injury. One study focusing on the association between dietary fat and injury prevalence in female runners found that those who obtained less than 30% of total daily calories from fat were more than twice as likely to suffer from an injury compared to those with fat intakes of 30% or more (Gerlach et al., 2008). The same study suggested that polyunsaturated fats were of particular importance in reducing injury risk due to their anti-inflammatory properties (Gerlach et al., 2008).

Similar to what was discussed in the previous section on muscle growth, fat isn’t ideal directly before or after an endurance session, but adequate fat throughout the day is incredibly supportive of endurance exercise.

To weigh or not to weigh?

If you’ve read some of my other posts, you won’t be surprised that I don’t track my fat intake. You totally can if that’s what works for you, but I have no idea—not even a ballpark—of how many grams of fat I eat in a day or what percentage of my calories come from fat. If macro or calorie counting isn’t for you either, it can be helpful to take some time to learn what different portion sizes look like—for example, a tablespoon of peanut butter or olive oil. When you can visualize portion sizes, it’s easier to create balanced meals and snacks that incorporate healthy amounts of fat, protein, and carbs.

Do what feels best for you—take note of how you feel before, during, and after you eat, and use that data to inform future decisions surrounding food and macros. Nutrition isn’t a fine art; you just need to find balance and variation. Strive to incorporate a diverse range of healthy fats and pair them with a source of protein and carbs to maximize macro- and micronutrient intake, satiety, and satisfaction. If you’re feeling comfortably full, energized, and content after eating, that’s a sign you’re doing something right.

Key takeaways

Fats play a role in so many bodily processes, including energy, hormone function, and vitamin absorption. Healthy, unsaturated fat is the best source of dietary fat, and while saturated fats aren’t inherently bad for you, they do come second to unsaturated fat in the nutritional hierarchy. Trans fats, on the other hand, are inherently bad for you, so let’s stay away from them as much as possible.

Omega-3 and omega-6 fatty acids are types of polyunsaturated fat that support a multitude of functions in our bodies, including brain and heart health. Most people already get enough omega-6 fatty acids, but omega-3 intake is often insufficient—incorporating things like fatty fish, walnuts, flaxseeds, and chia seeds can help you get more omega-3s.

Recommended fat intake is 20-35% of total daily calories, with a maximum of 10% coming from saturated fat and the rest from unsaturated fat. Within this range, the right amount of fat for you is dependent on your intake of other macronutrients, caloric needs, and goals, but regardless of what those are, fats are essential.

Beyond the nutritional benefits of fats, they just make food taste so much better. Cooking without oil sounds bland; chocolate without peanut butter sounds lonely; crackers without cheese sound incomplete; and if the influencers got one thing right, it’s avocado toast. Without fat, we’d die, and everything would stick to our pans, so let’s give credit where credit is due.

References

Gerlach, K. E., Burton, H. W., Dorn, J. M., Leddy, J. J., & Horvath, P. J. (2008). Fat intake and injury in female runners. Journal of the International Society of Sports Nutrition, 5(1). doi: 10.1186/1550-2783-5-1

Gershuni, V. M. (2018). Saturated Fat: Part of a Healthy Diet. Current Nutrition Reports, 7(3), 85-96. doi: 10.1007/s13668-018-0238-x.

Gora, A. (2022, August 17). Low fat diet: what are the pros and cons? Live Science. https://www.livescience.com/52851-low-fat-diet-facts.html

Hetlelid, K. J., Plews, D. J., Herold, E., Laursen, P. B., & Seiler, S. (2015). Rethinking the role of fat oxidation: substrate utilisation during high-intensity interval training in well-trained and recreationally trained runners. BMJ Open Sport & Exercise Medicine, 1(1). doi: 10.1136/bmjsem-2015-000047

Hjalmarsdottir, F. (2023, January 17). 17 Science-Based Benefits of Omega-3 Fatty Acids. Healthline. https://www.healthline.com/nutrition/17-health-benefits-of-omega-3

Kim, J. Y. (2021). Optimal Diet Strategies for Weight Loss and Weight Loss Maintenance. Journal of Obesity & Metabolic Syndrome, 30(1), 20-31. doi: 10.7570/jomes20065

Kunik, K. (2022, May 10). How Fat Helps Build Muscle, and the Best and Worst Fats to Eat. Livestrong. https://www.livestrong.com/article/428268-fat-intake-causes-muscle-growth/

Liu, A. G., Ford, N. A., Hu, F. B., Zelman, K. M., Mozaffarian, D., & Kris-Etherton, P. M. (2017). A healthy approach to dietary fats: understanding the science and taking action to reduce consumer confusion. Nutrition Journal, 16(1), 53. doi: 10.1186/s12937-017-0271-4

Lopez-Jimenez, F. (2023). What are omega-6 fatty acids? Can eating omega-6 fatty acids cause heart disease? Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/heart-disease/expert-answers/omega-6/faq-20058172#:~:text=Studies%20have%20not%20shown%20an,saturated%20fats%20in%20your%20diet.

Lordan, R., Tsoupras, A., Mitra, B., & Zabetakis, I. (2018). Dairy Fats and Cardiovascular Disease: Do We Really Need to Be Concerned? Foods, 7(3), 29. doi: 10.3390/foods7030029

Moll, J. (2023, October 18). Polyunsaturated Fat vs. Monounsaturated Fat: What's the Difference? Verywell Health. https://www.verywellhealth.com/monounsaturated-and-polyunsaturated-fats-differences-697740

Nutrition: Trans fats. (2018, May 3). World Health Organization. https://www.who.int/news-room/questions-and-answers/item/nutrition-trans-fat#:~:text=International%20expert%20groups%20and%20public,hydrogenated%20oils%20used%20in%20food%3F

Omega-6 fatty acids. (n.d.). Mount Sinai. https://www.mountsinai.org/health-library/supplement/omega-6-fatty-acids#:~:text=Along%20with%20omega%2D3%20fatty,and%20maintain%20the%20reproductive%20system.

Pendergast, D. R., Horvath, P. J., Leddy, J. J., & Venkatraman, J. T. (1996). The role of dietary fat on performance, metabolism, and health. The American Journal of Sports Medicine, 24(6 Suppl.), S53-8.

Perna, M. & Hewlings, S. (2022). Saturated Fatty Acid Chain Length and Risk of Cardiovascular Disease: A Systematic Review. Nutrients, 15(1), 30. doi: 10.3390/nu15010030

Quinn, E. (2023, July 5). Converting Fat to Energy: Understanding the Process. Verywell Fit. https://www.verywellfit.com/sports-nutrition-how-fat-provides-energy-for-exercise-3120664#:~:text=also%20produces%20heat.-,How%20the%20Body%20Uses%20Fat%20for%20Fuel,the%20stored%20carbohydrate%20(glycogen).

Semeco, A. (2023, March 14). Post-Workout Nutrition: What to Eat After a Workout. Healthline. https://www.healthline.com/nutrition/eat-after-workout