4 "Bad" Fats You Should Be Eating, According to Dietitians (2024)

As BFFs with their favorite bottle of olive oil and proud avocado toast aficionados, EatingWell editors were certainly more than happy to see the trends of chalky, fat-free cookies and air-pumped fro-yo fade away.

The low-fat era in the 1980s and 1990s continues to have some ripple effects on the food system and the reputation of certain products, it seems, especially regarding the whole family of fats. As a reminder, fat is not to be feared!

In addition to carbohydrates and protein, "fat is an essential macronutrient that plays several important roles in the body," says Lauren Harris-Pincus, M.S., RDN, a New Jersey-based registered dietitian, founder of NutritionStarringYOU.com and author of The Everything Easy Pre-Diabetes Cookbook.

These important functions include boosting the body's ability to absorb fat-soluble vitamins like A, D, E and K, producing certain hormones that support bone health, reproduction and muscle mass, and playing a role in cell structure, function and communication, Harris-Pincus confirms.

Plus, fat plays a major role in boosting your brainpower: "The brain is 60% fat, so fat consumption is important for cognition and memory," she adds.

The benefits of consuming fats don't stop there, says Mary Stewart, RD, LD, a registered dietitian and the founder of Cultivate Nutrition in Dallas.

"Fat delivers flavor and fullness to our meals," Stewart explains. And you can max out your health benefits by choosing the optimal amount and the right kinds, she says: "Consuming healthy fats is linked to reduced chronic inflammation, brain health, cardiovascular health and a stronger immune system."

Are Fats Bad for You?

All foods that contain calories from fat include a mixture of different types of fats, Stewart says. They fall into one of three categories.

• Saturated fat is found in animal products, such as meat, full-fat dairy and tropical oils. These fats are typically solid at room temperature since their chemical structure includes carbon molecules that are saturated with hydrogen atoms.
• Unsaturated fat is liquid at room temperature, again, due to its molecular makeup. These come in two types: monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs), both of which play a beneficial role in supporting our health, according to Stewart.
  • MUFAs "have extensively been researched to validate a positive impact on cardiovascular health, gut health and inflammation," Stewart says. You can score them via macadamia nuts, olives, avocados, olive oil, avocado oil, canola oil and peanut oil.
  • PUFAs "have been shown to reduce LDL cholesterol, increase HDL cholesterol and protect against cardiovascular and neurodegenerative diseases," Stewart notes. You might hear these broken down further into omega-6s (linolenic) and omega-3s (EPA and DHA). Get your dose from walnuts, flaxseed, pumpkin seeds, chia seeds, hemp seeds, soybean oil and canola oil.
• Trans fats can be found naturally in a handful of foods but used to be mainly spotted in some processed foods and fast foods that include vegetable oils altered in a way that made them more self-stable. These added trans fats have been phased out after being banned by the FDA.

So how can you determine which fats you should consume and which to limit?

As mentioned, research backs up the fact that unsaturated fats are a boon for your body in moderation, to the tune of 20% to 25% or so of total calories from fat. Think of experts flipping on the green light for these.

A yellow light goes to saturated fats; proceed with caution, but definitely don't avoid them at all costs, Harris-Pincus and Stewart agree.

Saturated fat has been controversial—per a 2023 article published in Current Opinion in Endocrinology, Diabetes and Obesity—in research communities and in the public conversation over the years and has been deemed as a "bad fat" by many, Stewart says. "But it's actually an important part of our health on a cellular level."

Fatty acids (both saturated and unsaturated) form the structure of our cell membranes, which makes the cells fluid, allows nutrients to enter the cells, and ushers waste out. Some studies have hinted that a very high saturated fat intake is associated with a greater risk of cardiovascular disease, but other research calls that theory into question. As experts continue to learn more, to find a happy medium, aim to follow the 2020-2025 Dietary Guidelines for Americans' recommendation for up to 10% of fats from saturated sources. If you have any current heart health risk factors, a family history of heart disease or a previous diagnosis of high cholesterol, your doctor or dietitian may also suggest limiting saturated fat more.

The trans fats are the only ones that we'll switch the red light on for.

"Artificial trans fat is a type of fat we definitely want to steer clear of, as it's associated with increased risk of chronic conditions like diabetes, heart disease and other inflammatory-related conditions," Stewart says.

Since the science is so strong about the health harms of these artificial trans fats, the FDA announced in 2015 that food producers had until 2020 to eliminate trans fats from their recipes. The amount left in the food system should be sparse, but trace amounts might still be in circulation.

"One of the best ways to circumvent this harmful fat is to read the ingredient list and avoid products that list partially hydrogenated oil in products like cookies, pie, cakes, crackers and avoid deep-fried foods as they are usually fried in oils containing trans fat," Stewart says.

4 "Bad" Fats You Should Eat

After that reminder that nuts, seeds, vegetable-based oils and avocado—the common "good fats" you're likely familiar with—are still your best bets, Stewart and Harris-Pincus share their picks for the best under-loved and under-used fats they consume in moderation (and recommend clients do, too).

Whole Eggs

Don't toss that yolk! Eggs, in their whole form, including the yolk and white, are packed with protein and some fat, a macronutrient mix that supports muscle mass and sustained energy.

"Eggs also have a healthy dose of vitamins and minerals like choline, vitamin D, iron, zinc and B vitamins," Stewart says, and nearly all of those micronutrients are tucked away in the egg yolk. "This winning combo will support immune health, brain health, and fight inflammatory conditions."

While eggs do contain cholesterol, dietary cholesterol consumption does not appear to impact cholesterol levels directly, Harris-Pincus says. Hence, she says that "up to one egg per day is fine for most people."

Whole Milk Products

For individuals who are among the 65% of the world's population, per a 2023 review in the International Dairy Journal, who deal with some level of malabsorption of lactose (the natural type of sugar in dairy), you'll still want to steer clear when possible. But for those who can consume milk without digestive discomfort, dairy has a "unique nutritional profile," Harris-Pincus says. And you need not stick to skim milk, nonfat yogurt or fat-free cheese.

"Whole milk is a great source of protein and offers a variety of vitamins and minerals, like vitamin B12, calcium, potassium and magnesium," she explains.

According to a study published in December 2022 in The American Journal of Clinical Nutrition, males who consumed the most dairy-derived saturated fats had a lower risk for heart disease, higher HDL and lower triglycerides than their dairy-free peers.

Aim for three total servings of dairy (1 cup of yogurt, kefir or milk, 1½ ounces of cheese, ⅓ cup shredded cheese) per day. If desired, mix and match whole, low-fat and nonfat.

Butter

While we'd never suggest you stray from cooking and finishing with olive oil, avocado oil or your other go-to, there's certainly a time and place for butter (in baked goods, for basting) and its clarified cousin, ghee. Nothing compares to the rich flavor both provide. Plus, ghee and butter contain butyric acid, a short-chain fatty acid known to support gut health and reduce overall inflammation, per a 2021 article published in Gut Microbes.

"Another benefit of butter and ghee is that they offer 11% to 13% of your daily value of vitamin A in just 1 tablespoon. Vitamin A supports our immune system and eye health," Stewart says.

Stick to 1 tablespoon or less per day.

Coconut Oil

As a staple of the keto diet, paleo diet, vegan diet and more, "coconut oil tends to wear a 'health halo,' and although it's a plant-based oil, it's high in saturated fat, which has been shown to potentially raise levels of the 'bad' kind of cholesterol, LDL," Harris-Pincus says. At the same time, she says, "there is some evidence that coconut oil can raise the 'good' HDL, although more research is needed."

Coconut oil contains a type of saturated fat called medium-chain triglycerides (MCTs), which has been shown to possibly help those who use it manage weight, decrease insulin resistance and reduce their risk for metabolic syndrome, Stewart adds. Another April 2022 study in the Journal of Functional Foods suggested the intake of MCTs can benefit the gut microbiome and metabolic health.

Until more is known, give it a shot every so often, but don't use it for every oil occasion, Harris-Pincus recommends.

"If you enjoy the flavor of coconut oil, feel free to use a modest amount in your cooking—but not because you believe it is inherently healthier than other oils like monounsaturated olive, avocado or canola oils," she says.

The Bottom Line

Fat is an important macronutrient that promotes satisfaction from meals and adds flavor to them, all while potentially supporting health and longevity. While unsaturated fats should be the most prominent source of calories from fat in your diet, most populations can enjoy saturated fats in moderation.

You might even snag some health benefits from a few of the previously smeared "bad" fats, including butter, ghee, coconut oil, whole milk products and whole eggs.