Fat plays a fundamental role in a healthy diet. The macronutrient is necessary for cellular growth, supporting healthier skin and hair and regulating the body’s metabolic functions. Fats keep our hormones in balance and help us absorb key nutrients like vitamins A, D, E and K (there’s a reason they’re called fat-soluble).
With 9 calories per gram, fats are the most calorically dense macronutrient — more than double that of protein and carbohydrates — which both contain 4 calories per gram. From a pure numbers perspective, it seems obvious as to why we historically thought high-fat foods were responsible for weight gain.
However, we now know that’s not the case. “Eating fat doesn’t make you fat,” says Dr. Frank Sacks, professor of cardiovascular disease prevention at the Harvard T.H. Chan School of Public Health. “Excess calories can come from fatty or high-carbohydrate foods, including added sugars [found in many processed foods] and that is what you need to be careful about.”
Healthy fats play a key role in building and maintaining a healthier lifestyle and can even help with weight loss.
Healthy fats include poly- and monounsaturated fats from sources like vegetables, nuts, seeds and fish. As for saturated fats, which come mostly from animal sources and a few tropical plant sources such as coconut and palm, limit these, but don’t feel like you should exclude them entirely. Small amounts of saturated fats are still found in healthy foods like lean beef, chicken thighs, salmon, eggs, whole-milk dairy and coconut-based products and foods that also come packaged with quality protein, fiber and essential vitamins and minerals like calcium, choline, vitamin D and magnesium.
Fat is an indispensable ingredient in the kitchen. For example, healthy oils, like olive oil, can be used to cook and sear lean proteins, baste vegetables, dress whole grains, wilt dark leafy greens and caramelize onions and nutrient-dense root vegetables.
As healthy eaters and exercisers, you also likely know fat is both satisfying and delicious: Think of how a hefty slather of nut butter transforms banana or apple slices or upgrades oatmeal. It not only tastes better, but it also fills you up faster. (Remember, it’s twice as calorie-dense as carbs and protein.) Scientifically speaking, fats stimulate the release of a hormone called cholecystokinin (CCK) that promotes short-term satiety, so you know to stop eating sooner, rather than when you realize you’re overly full.
You’re likely to have a much more difficult time losing weight if you are hungry all the time. Foods higher in fat take longer for our system to digest, unlike carbs, which begin their digestion process in our mouths, fats don’t begin to break down until they reach our small intestine.
They also don’t raise blood sugar and spike insulin in the same way as carbohydrates and combining fat with high-fiber foods like whole grains and veggies may increase the satiating potential of fat even more.
Our brain is more than 60% fat and needs certain fats to thrive. In particular, omega-3 fatty acids play an essential role in brain development and function, helping boost memory, enhance our speaking ability and providing anti-inflammatory and antioxidant properties that slow mental deterioration. New research even suggests a higher level-functioning brain is key to more successful weight loss.
Fats are necessary to break down fat-soluble vitamins A, D, E and K as well as certain phytonutrients like lycopene in tomatoes and lutein in dark leafy greens — powerful antioxidants that have anti-cancer properties. This is even more reason to ditch store-bought fat-free and low-fat dressing (which are typically loaded with added sugar and preservatives) and try these healthy oil-based dressings.
Once we’ve reached a calorie deficit, our bodies start to break down and burn fat for energy. Diets higher in carbohydrates may take longer to get into the fat-burning stage, as there’s more glycogen stores to burn through, a reason lower-carb diets like keto and Paleo tend to be more successful in burning fat for energy.
Including more healthy fat in your diet can be beneficial for weight loss. However, before committing to a keto or Paleo diet (which can be hard to sustain), make sure you’re eating balanced meals regularly that include all three macronutrients. Combined with regular movement, doing so is the most sustainable and successful way to lose weight and keep it off.