To combat body fat and live a longer, healthier life, you have to eat fat—the right kind that is. It’s actually quite simple, and new research out of Harvard is piling on the reasons why you should reacquaint yourself with fatty foods: Replacing five percent of your caloric intake from so-called bad fat (like trans and saturated fat found in red meat and lard) with healthy fat (unsaturated) from plant-based foods like olive oil can reduce your risk of death by 27 percent. Twenty-seven percent!
What the Science Says
In the study, published in JAMA Internal Medicine, researchers compiled information from 126,233 participants from two very large long-term studies. Participants answered surveys every 2-4 years about their everyday diet, lifestyle, and health for up to 32 years. During the followup, 33,304 deaths were documented. While a bit morbid, the researchers were able to examine the relationship between dietary fat and overall death, as well as deaths due to cancer, cardiovascular, neurodegenerative, and respiratory disease.
Trans fats—which are being phased out of most foods thanks to the FDA—had the worst adverse impact on health. For every 2 percent higher intake of trans fat, there was a 16 percent higher chance of premature death. The same trend was seen with a greater consumption of saturated fats and mortality risk: When compared with the same number of calories from carbohydrates, every 5 percent increase in saturated fat consumption was linked with an 8 percent higher risk of overall mortality.
Meanwhile, higher intakes of unsaturated—polyunsaturated and monounsaturated—good fats was associated with an 11 percent and 19 percent lower risk of death respectively compared with the same number of calories from carbohydrates. Specifically, it’s the omega-6, found in most plant oils, and omega-3 fatty acids, found in fish and soy and canola oils, natural to polyunsaturated fats that keeps you healthy and wards off death.
How to Replace Bad Fat With Healthy Fat
The health benefits of certain types of fats were largely dependent upon what people were replacing them with, the researchers say. People who replaced bad saturated fats with good unsaturated fats—especially polyunsaturated fats—had a significantly lower risk of death overall, as well as a lower risk of death from CVD, cancer, neurodegenerative disease, and respiratory disease, compared with those who maintained high intakes of saturated fats.
Interestingly, kicking out both good and bad fats didn’t have as great of an effect. The researchers found when people replaced saturated fats with carbs (instead of good fats), they had only a slightly lower mortality risk. What’s more, replacing total fat with carbs altogether actually caused slightly higher instances of death.
It’s likely because carbs in the American diet tend to be primarily refined starch and sugar, which have a similar influence on mortality risk as saturated fats. (Read our dossier on the 13 best sources of whole grains.)
“Our study shows the importance of eliminating trans fat and replacing saturated fat with unsaturated fats, including both omega-6 and omega-3 polyunsaturated fatty acids. In practice, this can be achieved by replacing animal fats like red meat with a variety of liquid vegetable oils,” senior study author Frank Hu said in a press release.
To up your intake of healthy fat, check out the best sources derived from plants and animals.
Not only are eggs considered the “perfect protein” (6g per egg) for containing all essential amino acids, they’re packed with vitamin D, riboflavin, and vitamin B12 to boot. The yolk contains heart-healthy fat, including omega-3 fatty acids, lutein, choline, and selenium. There’s only 1.6 grams of saturated fat per large egg. And that’s not all. Research suggests consuming conjugated linoleic acid (CLA), found in egg yolks, and hitting the gym for at least 4.5 hours per week significantly reduces body fat–not weight. More research discovered CLA has a direct impact on the reduction of some forms of colon cancer, too.
2. Fruit and Vegetable Oils
Coconut oil is enjoying a recent resurgence; the fatty acid MCT (medium-chain triglyceride) has antibacterial, anti-fungal, and even fat-burning properties. Research has found people lose more weight, especially belly fat, when they consume coconut oil. Algae (monounsaturated fat), olive (monounsaturated fat), peanut (monounsaturated fat), walnut (omega-3 fatty acid alpha-linolenic) all have their unique health benefits and work best in different scenarios; read here for which to cook with and eat raw.
3. Nuts and Nut Butters
Cashews, almonds, and hazelnuts are chock-full of monounsaturated fats, which can keep your cholesterol in check by lowering bad LDL cholesterol and raising good HDL levels. A 2013 study of nearly 190,000 people published in the New England Journal of Medicine found those who ate a one-ounce serving of nuts daily decreased their risk of dying from any cause, including cancer and heart disease, by 20 percent. “These people also tend to be leaner, which is a curious finding, considering a serving of nuts is 160 to 200 calories,” says study researcher Charles S. Fuchs, M.D. Fuchs suggests that nuts’ positive effect on energy balance, metabolism, and satiety likely explain how the high-fat snack can actually keep your weight in check. Rotate what you snack on: pistachios, walnuts, peanuts, cashews, and Brazil nuts all have their own nutrient profile. Add nut butters to your diet too. Used as a dip, spread, or smoothie add-in, you can boost your protein and healthy fat intake with almond butter in so many dishes.
Olive oil usually gets the health halo, but the fruit itself has tons of antioxidants that can help prevent heart disease and healthy monounsaturated fat which can increase good cholesterol. The oleic acid olives contain can reduce blood pressure, too.
The CDC suggests people who eat, on average, half a medium avocado daily are healthier than those who skip the fruit, more closely adhere to dietary guidelines, consume 48 percent more vitamin K, 36 percent more fiber, 23 percent more vitamin E, 16 percent more potassium and 13 percent more magnesium, have higher intakes of healthy (monounsaturated and polyunsaturated) fats, have higher good HDL cholesterol, weigh about 7.4 pounds less and have lower BMIs, and have 50 percent lower odds of developing metabolic syndrome. Need we go on? Make some avocado toast already.
6. Fatty Fish
Fish high in omega-3 fatty acids, like salmon, tuna, trout, mackerel, sardines, and herring. These fish have an impressive combination of protein, healthy fats, vitamin D, and marine oils, which are essential for a healthy nervous system. You can bulk up and boost your total-body health by eating more fatty fish.
Flaxseeds and chia seeds are an amazing plant sources of omega-3 fatty acids. Both are are brimming with fiber, perfect for maintaining digestive health and lowering cholesterol. Toss either, or both, in your oats and smoothies for some sustained energy.