Tuna also packs a high amount of healthy fats and omega-3s. We're talking both the conveniently canned stuff and the kind you find at your favorite sushi spot. It's versatile—tuna steaks, tuna burgers, tuna salad, the options are endless—so it's pretty easy to fit into your diet. Like salmon, you should limit your intake to about 12 ounces (two meals) a week to avoid overexposure to things like mercury that can be found in small amounts in seafood.
Fats also help us digest important fat-soluble vitamins such as vitamins A, D, E, and K that keep our brains, cells, hormones, tissues, hair, skin, and nails healthy (1). Fat provides the structural component to many cell membranes which are essential for cellular development and carrying various messages through our body quickly via hormones. In fact, fats are vital to hormonal health. I’ve worked with many clients recovering from eating disorders or very restrictive diets who have gone years without periods due to their low body fat percentage. There’s a fine line between wanting to be “toned” and “ripped” and being a healthy woman able to provide your body with enough fat reserves for healthy hormones and hormonal production. Fat is crucial for our bodies!
Eating foods with fat is definitely part of a healthy diet. Just remember to choose foods that provide good fats (monounsaturated and polyunsaturated fats) and balance the amount of calories you eat from all foods with the amount of calories you burn. Aim to eat a dietary pattern that emphasizes intake of vegetables, fruits, and whole grains; includes low-fat dairy products, poultry, fish, legumes, non-tropical vegetable oils and nuts; and limits intake of sodium, sweets, sugar sweetened beverages and red meats. Doing so means that your diet will be low in both saturated fats and trans fats.
Cutting back on saturated fat will likely have no benefit, however, if people replace saturated fat with refined carbohydrates. Eating refined carbohydrates in place of saturated fat does lower “bad” LDL cholesterol, but it also lowers the “good” HDL cholesterol and increases triglycerides. The net effect is as bad for the heart as eating too much saturated fat.
Polyunsaturated fats can also be healthy. The two main types are omega-3 and omega-6 fatty acids, essential fats our bodies need for brain function and cell growth. Omega-3s are beneficial for every aspect of heart health, and are mostly found in fish and algae, nuts, and seeds. “Other polyunsaturated fats, [omega-6s], can be found in certain plant-based oils,” Hunnes adds. “They’re not particularly harmful, but not necessarily beneficial the way omega-3s and monounsaturated fats are.” Omega-6s work alongside omega-3s to lower LDL cholesterol, but research suggests that eating more omega-6 than -3 may contribute to inflammation and weight gain, so the key is to make sure your omega-3 intake is always higher.
When comparing saturated vs. unsaturated fat, it’s generally recommended that unsaturated fatty acids should make up the majority of your fat intake. One study in 2015 showed that replacing just 5 percent of calories from saturated fats with an equal amount from polyunsaturated or monounsaturated fatty acids resulted in a 25 percent and 15 percent reduced risk of heart disease, respectively. (6) However, both offer a unique set of benefits and can be included in moderation as part of a well-balanced and healthy diet.
Avoiding trans fats can be tricky because food labels can be misleading. Even though trans fats have been banned by the FDA, foods with less than 0.5 grams of trans fat in a serving can read 0 grams of trans fat on the food label. To determine if the food contains trans fats, check the ingredient list for “hydrogenated” or “partially-hydrogenated” oil. While 0.5 grams may seem small, eating several portions of foods containing some trans fat may be enough to affect your health.
Omega-3 fatty acids may help prevent and even treat heart disease and stroke. In addition to reducing blood pressure, raising HDL, and lowering triglycerides, polyunsaturated fats may help prevent lethal heart rhythms from arising. Evidence also suggests they may help reduce the need for corticosteroid medications in people with rheumatoid arthritis. Studies linking omega-3s to a wide range of other health improvements, including reducing risk of dementia, are inconclusive, and some of them have major flaws, according to a systematic review of the evidence by the Agency for Healthcare Research and Quality.
Plus, eating a good variety of foods high in fat can also boost brain function. Loading up on the healthy fat foods can soothe inflammation and promote blood flow to the brain to enhance cognitive function. In particular, medium-chain fatty acids, omega-3 fatty acids and unsaturated fats play a critical role in brain function and development. (11, 37, 38)
Wild-caught salmon, olive oil, avocados, walnuts, flaxseeds, chia seeds and hemp seeds are packed with omega-3 fatty acids. Ideally, it’s best to get omega-3 fatty acids from fish sources which contain better converting and more bioavailable forms of DHA and EPA. Plant-based omega-3 rich foods like flax seeds, chia seeds, and hemp seeds must be converted in the body from ALA to DHA and EPA, that conversion doesn’t yield as optimal levels of omega-3 compared to food sources like salmon, mackerel, and other fish.
Consuming monounsaturated fatty acids may protect you from heart disease by lowering LDL and total cholesterol, improve the function of blood vessels, help prevent depression, improve body composition, and improve insulin sensitivity and blood sugar control (10,11). Monounsaturated fats have even been shown to reduce cancer risk (12). Oils rich in monounsaturated fats also contain the antioxidant vitamin E which has many health benefits.
Fat came under scrutiny in the 1960s when the sugar industry paid Harvard researchers to publish a review on sugar, fat, and heart disease. The sugar industry funded the research to cover up warning signs, which emerged in the 1950s, that sugar caused heart disease (1). Shifting the blame away from sugar, the researchers singled out saturated fat as the cause of heart disease.
In fact, while carbohydrates from whole grain, fiber-rich sources can be beneficial, refined carbohydrates found in foods like candies, white bread, baked goods and sweets provide little in terms of nutrition apart from extra calories and sugar. According to a study in the Journal of the American College of Cardiology, refined carb intake was associated with a higher risk of coronary heart disease while consumption of whole grains and polyunsaturated fats was linked to a lower risk. (6)
Fats are commonly classified as good fats and bad fats. Good fats are all fats which are naturally found in foods; they are not heat processed, and are therefore not damaged. Especially important good fats are the essential omega-3's, but any fat that's normally found in food- like avocados, eggs, flaxseed, olives, coconut and nuts can be a good fat when consumed in a healthy diet.
Olives are rich in monounsaturated fat. Add them to salads or snacks, and cook with olive oil whenever possible as part of a heart-healthy diet. “Olive oil is made up of triglycerides that contain a very large percentage of monounsaturated fatty acids,” says Janet Bond Brill, PhD, a registered dietitian and author of Cholesterol Down: 10 Simple Steps to Lower Your Cholesterol in 4 Weeks Without Prescription Drugs and Prevent a Second Heart Attack: 8 Foods, 8 Weeks to Reverse Heart Disease. “Up to 80 percent of olive oil is monounsaturated, primarily the omega-9 fatty acid known as oleic acid. The high monounsaturated fatty acid content of olive oil is extremely cardioprotective — it cuts your ‘bad’ cholesterol level, helps prevent atherosclerosis, and can bump up your level of HDL, the ‘good’ cholesterol.” Try this simple olive-based side dish of chard with green olives, currants, and goat cheese.
Walnuts have earned their superfood status in part because of their fats. They are one of the few foods to deliver alpha-linolenic acid (ALA), a type of omega-3 fat thought to protect against heart disease. Toast them to bring out their flavor and extra crunch, then sprinkle about a tablespoon on yogurt or fold some into muffins or your morning oatmeal.
Are you afraid of fats? If so, you’re not alone. Fat in foods has been vilified in America for the past few decades, as low-fat and non-fat foods became the norm and we were told that cutting even healthy fats out of the diet would help us get the body we want. In fact, it’s one of the biggest nutrition lies that the public’s been told throughout history.
Other studies have confirmed the health benefits of following a low-carb diet rather than a low-fat diet. In one study, women lost more weight following a low-carbohydrate diet than a low-fat diet (5). In addition to weight loss, studies also show that low-carb, high-fat diets reduce inflammation, regulate blood sugar levels, and reduce triglycerides while raising HDL cholesterol levels (6,7).