A Guide to Healthy Fats vs. Unhealthy Fats

Eating fats is one of the keys to health and longevity—as long as you eat the healthy kind.

Americans have a somewhat troubled history with fat. It's a key macronutrient (one of three, along with protein and carbs), but it's created a lot of fear and misinformation in the general public over its nutritional value.

Scientific studies in the mid-1900s showed a link between high-fat diets and heart disease. Under the guidance of their doctors, many Americans began to move toward lower-fat diets—even people who weren't at high risk for heart disease. As a result, by the late '80s, the low-fat diet became almost an ideology, with devotees subsisting on fat-free yogurt, margarine, and carbohydrates.

Since then, further research and study have shown that there's a lot more nuance to the role that dietary fats play in our overall health. In recent years we've even seen the rise of diets like the Ketogenic diet, which places a strong emphasis on consuming healthy fat in amounts up to 70 percent of recommended daily caloric intake.

With all this conflicting information, it can be hard to know how to follow a healthy diet. Should we be avoiding fat, or scarfing it down? Which fats are "good" and which are "bad"? We tapped a nutritionist to get the low-down on healthy vs. unhealthy fats so you can spend less time scouring the internet for scientific studies, and more time enjoying balanced meals—which, yes, should include healthy amounts and types of fat.

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Healthy vs. Unhealthy Fats

First, it's true that not all fats are healthy. As a general rule, saturated and trans fats are considered unhealthy, while unsaturated fats are considered moderately healthy. However, it's not that black-and-white.

For example, avocados are made up of mostly monounsaturated fats, but do contain a small amount of saturated fat. So, they're a mostly nutritious food that should be eaten in moderation.

Trans Fats and Saturated Fats

What foods contain the "bad" types of fat?

According to the American Heart Association, foods that are high in saturated fats include red meat like beef, lard, cream, butter, cheese, and many fried foods.

Trans fats are a form of unsaturated fat that can be found naturally in small amounts in meat and dairy products. But most trans fat is created through an industrial process called hydrogenation, which extends the shelf life of vegetable oils.

Because of their low cost and far-off expiration dates, trans fats are found in many shelf-stable and processed food items. Many restaurants use trans fat in their deep fryers, since they are changed less often than their healthier fatty counterparts.

In other words, trans fats can be found in processed foods like crackers and cookies and in lots of fast food like french fries.

Diets that include a lot of saturated and trans fats have been shown through numerous research studies to raise your "bad" cholesterol (LDL) and lower your "good" cholesterol (HDL), which can increase your risk of heart disease.

"The scientific rationale for decreasing saturated fat in the diet has been and remains based on well-established effects of saturated fat to raise low-density lipoprotein (LDL) cholesterol, a leading cause of atherosclerosis," according to a Presidential Advisory board in a major review published by the American Heart Association.

Consuming trans fats has also been linked to increased inflammation in the body, which can result in a number of chronic health conditions from diabetes to arthritis.

Unsaturated Fats

Healthy fats, on the other hand, are typically monounsaturated and polyunsaturated fats, and naturally come from whole foods including fruits, nuts, seeds, and fish. When you hear people raving about the benefits of Omega-3 fatty acids, for example, they're talking about a heart-healthy polyunsaturated fat that can be found in fatty fish, algae, and flaxseeds.

"Healthy fats help you stay healthy and live an energized, disease-free life, while unhealthy fats can contribute to chronic disease and sap your energy. And they've been shown to increase your risk of certain health conditions," says Kate Geagan (MS, RD) a consultant to Pompeian and a sustainable food and nutrition expert.

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Benefits of Eating Healthy Fats

There are some important health benefits in including the right kinds of fat into your diet.

"Fats are far more than just the number of calories or grams of fat on the Nutrition Facts panel, or even the 'type' of fats that we think about (such as monounsaturated fats)," says Geagan. "When it comes to fats, some play a vital role in longevity and vitality because they provide a whole beneficial spectrum of protective, healing benefits in every bite."

According to the American Heart Association, including unsaturated fats in your meals and snacks lowers rates of cardiovascular disease and all-cause mortality, as well as providing essential nutrients your body can't produce itself.

Olive oil, for example, is a staple for people who follow the health-promoting Mediterranean Diet, and for good reason. High-quality olive oils like Pompeian Extra Virgin olive oil are rich in powerful polyphenols (such as oleocanthal and oleuropein) that significantly reduce inflammation and protect your cells from DNA damage.

"Daily consumption of EVOO can lower blood pressure and improve the function of the lining of the blood vessels," says Geagan. "Researchers have found that this abundance of antioxidants in EVOO may provide additional protection against cardiovascular disease and stroke. One landmark study found that for every 10 grams per day increase in EVOO consumption, cardiovascular disease risk dropped by 10 percent."

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How Much Healthy Fat to Eat

If unsaturated fats are good for us, does that mean we can eat them in unlimited quantities?

You might want to put away the jumbo-sized guac container. As you might have predicted, the old adage "everything in moderation" applies to healthy fats, as well. "The USDA recommends healthy adults aim for 20-35 percent of their calories from fat, while for children it can be as high as 40," advises Geagan.

She recommends that people start making small swaps that don't increase daily caloric value. For example, switching out vegetable oil for olive oil in cooking, or using avocado on a sandwich in place of mayo or extra cheese. Going over the recommended daily values for healthy fats will not increase the benefits, and could make it hard to maintain a healthy weight (which is another key component of overall health).

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Best Sources of Healthy Fats

Luckily, healthy fats can be found in an abundance of delicious, satiating foods: Geagan especially recommends these top natural sources of healthy fats:

  • Olive oil
  • Avocados
  • Seeds
  • Nuts and nut butters (just watch out for added sugar in store-bought brands)
  • Oily, omega-3-rich fish (like salmon, barramundi, tuna, sardines, mackerel, and trout)

For a well-balanced meal, try seared salmon with Israeli couscous, which is rich in omega-3s and dressed with olive oil, or add an almond crust to your weeknight chicken. Reach for healthy snacks like mixed nuts (just make sure they're not roasted in vegetable oil!), half an avocado sprinkled with salt and chili flakes, or no-bake nut and seed bars. Or dip crunchy veggies and healthy crackers into creamy, olive-oil-drizzled hummus.

Enjoy the fat sources you choose to include in your diet. "Taste and flavor are key to enjoying your food and your life!" she says. "One of the really amazing benefits of the Mediterranean diet is that its delicious taste is one of the key secrets behind its power to effect such lasting change. People are much more willing to stick with an eating style they find filled with delicious food." And good fats are absolutely part of that.

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