Fat has had quite the parley in dietary discussion spaces – the low-fat movement starting in the 1980s told us we should eliminate fat, while high-fat diets like keto tell us the opposite. 

How do you know where the answers lie? The reality is, fat is engrained in American diets. It’s in the oil we use in the pan, the fish we cook, the vegetables we eat (think avocado). It’s also an essential part of a healthy diet and is crucial for energy, cell function, hormone production and nutrient absorption.

What are the healthiest fats?

Not all fats are created equal, says registered dietitian Chris Mohr, but overall fat is essential to our diet. According to Mohr, the “healthiest” fat is one we need but often don’t get enough of – omega-3s.

Omega 3s are polyunsaturated fats that are essential nutrients, meaning our bodies don’t make them on their own. But according to a study based on the National Health and Nutrition Examination Survey, 68% of adults and over 95% of children consume less than the recommended amount.

Omega-3s are most commonly found in fish, although you can also get them from dark leafy greens, flaxseeds, hempseeds and walnuts. Omega-6s, another type of polyunsaturated fat, are also essential, but Mohr says we don’t have trouble getting those into our diet because they’re found in many cooking oils, nut butters and eggs. 

Ideally, Mohr says, you’re getting a balance of fat sources. According to the Dietary Guidelines for Americans, fat should make up between 20-35% of our daily caloric intake, with less than 10% of that coming from saturated fats. The guidelines also say to avoid trans fats, which are known to increase the risk of heart disease, stroke and type 2 diabetes.

“Too much of some types of fat may not be best for us, while others are fantastic,” Mohr says. "There’s some nuance in terms of not just quantity but also the quality of the fat we’re eating.”

There are four major types of fats – trans fats, saturated fats and two types of unsaturated fats:

What are the benefits of omega-3?

Omega-3 fatty acids support heart health and may also help lower the riskof cancer, cognitive disease and eye disease. According to Mohr, a lack of omega-3s can present itself in the form of dry skin and brittle hair. Studies have also shown a connection to mood – omega-3s have anti-inflammatory properties that may alleviate depression.

The Dietary Guidelines for Americans recommends at least 8 ounces of seafood per week for adults consuming a 2,000-calorie diet. Pregnant or breastfeeding individuals are advised to consume between 8 and 12 ounces of low-mercury fish per week for developmental benefits for the baby. One serving is about 4 ounces of fish.

Fish is the most common source of omega-3s – salmon and tuna are tried-and-true favorites, but Mohr recommends trying out herring, sardines and anchovies too. You can also get some from leafy vegetables, vegetable oils, nuts, flax seeds and flaxseed oil. 

For those who don’t consume enough fish, Mohr recommends looking into omega-3 supplements that are at least 500 milligrams. For non-fish eaters, check out an algae oil supplement, which is where even the fish get their omega-3 content.

Is saturated fat bad?

Much of the public’s knowledge about saturated fat is that it increases low-density lipoprotein cholesterol (“bad cholesterol”) and the likelihood of heart disease. But some recent studies challenge current guidelines and suggest there is less of a link between saturated fat and increased risk of cardiovascular disease than previously thought. 

According to Mohr, saturated fat is “one piece of the puzzle” when it comes to cardiovascular disease risk. Often when people are told to reduce saturated fat in their diets, they instead increase their intake of refined carbohydrates like added sugars, Mohr says. This may lower LDL, Mohr says, but will also lower high-density lipoprotein cholesterol ("good" cholesterol) and raise triglycerides. It may be healthier to replace saturated fat with unsaturated fat in the diet rather than just focusing on reducing saturated fat. 

The takeaway then, he says, is to focus most of your fat intake on monounsaturated and polyunsaturated and replace saturated fat intake with unsaturated fats when you can. 

“Fats are essential, we just need to be wary of what we’re eating, how much we’re eating,” Mohr says.

USA Today