Seed oils are controversial. But is animal fat really healthier? Experts settle the debate

The seed oil versus animal fat debate has gone from a niche topic among wellness influencers on social media to an entire movement.

Perhaps you’ve already heard of the “Hateful Eight” — not the movie, but the list of oils to supposedly avoid, including canola and corn. Seed oil naysayers claim these plant-based cooking oils are “toxic” or lead to chronic diseases, neither of which are backed by scientific evidence.

Many critics promote swapping seed oils for animal fats like butter, beef tallow and lard. Just two decades after the fat-free era of the early 2000s, people are now fighting about which fat is best.

While it’s true that not all fats or oils are equal, the recent discourse has left many confused. So, which is better for you — seed oils, or animal fats?

What are seed oils?

Seed oils are a type of vegetable oil extracted from the seeds of plants, Dr. Nate Wood, director of culinary medicine at the Yale School of Medicine, tells TODAY.com.

Popular seed oils include:

All seed oils are vegetable oils, but not all vegetable oils are seed oils. Other vegetable oils may be extracted from the fruit or pulp of the plant, such as olive, avocado and coconut oils.

“Seeds are a high-fat food … so we take the seeds and extract the all the fat out of them and leave behind the fiber and the protein,” Wood says.

These seeds go through multiple processes to become cooking oil.

First, the seeds are usually pressed, which extracts the oil by crushing the seeds, Lena Beal, cardiovascular dietitian and spokesperson for the Academy of Nutrition and Dietetics, tells TODAY.com.

Seed oil may also go through chemical extraction, which uses solvents to separate the oil from the seeds.

After extraction, most seed oils are refined to remove particles, improve the taste and shelf-life, and make the oil more heat-stable.

Are seed oils healthy?

Seed oils are healthy when consumed in moderation as part of a healthy, balanced diet, the experts note.

“Seed oils are largely unsaturated fats, which we know are really healthy,” says Wood. These include polyunsaturated and monounsaturated fats, which are “good” fats.

The goal is to consume more good fats and fewer “bad” or unhealthy fats (saturated and trans fats), per the American Heart Association.

Unsaturated fats can lower LDL, or “bad” cholesterol, and boost HDL, or “good” cholesterol. “They’re really good at protecting against heart disease,” says Wood. Unsaturated fats in these oils can also lower the risk of stroke, support brain function and improve blood sugar levels, TODAY.com previously reported.

Seed oils are generally higher in polyunsaturated fats, which provide essential omega fatty acids that our body can’t produce on its own. “Most seed oils have a good amount of omega-6, and smaller amounts of omega-3,” says Beal.

Unrefined seed oils contain more nutrients than highly refined seed oils, but both can be part of a healthy diet, the experts note.

Why are seed oils controversial?

Seed oils get a bad rap for a few reasons, says Wood. Many critics believe seed oils are harmful because they have a high omega-6 content and they’re found in ultraprocessed foods. Some people also say the refining process makes seed oils “toxic.”

Nutritional science can be confusing, but any claims that seed oil is poisonous are “scientifically wrong,” Gardener says.

Omega-6s in seed oils

Seed oils contain high levels of omega-6 unsaturated fatty acids, which are controversial because some are linked to inflammation, particularly when a person doesn’t get enough anti-inflammatory omega-3 fatty acids, TODAY.com previously reported.

While it’s true that our body uses some omega-6s as precursors to create inflammatory molecules, this can be a good thing, says Wood.

“Part of what (omega-6s) do is they help the immune system work on an inflammatory response,” Christopher Gardner, Ph.D., professor of Medicine at Stanford University, tells TODAY.com. This is how the body attacks germs, fights infections and heals injuries, Wood adds.

Omega-6s play a smaller role than omega-3s in protecting heart health, but they can still lower LDL — which is why the AHA supports including seed oils as part of a healthy diet.

“We have decades of evidence on how those omega-6 fatty acids are heart-healthy when you replace the saturated fats in your diet,” says Gardener.

However, it’s important to get a balanced ratio of omega-6s to omega-3s, which are found mostly in fish and nuts, says Wood. The American diet is very high in omega-6s. “The reason isn’t because we’re cooking with canola oil. It’s because we’re eating lots of ultra-processed foods,” says Wood.

Seed oils in processed foods

We know ultraprocessed foods, aka junk foods, are bad for us, says Wood. Research shows they’re linked to poor health outcomes and mortality. “Ultraprocessed foods also have lots of seed oils in them,” says Wood. People conflate these two ideas and blame seed oils, says Gardener.

“They’re attributing the adverse health consequences to the seed oils, when, in fact, it’s the junk food as a whole. It’s the sugar, the salt, the added ingredients,” says Gardener. Ultraprocessed foods often contain refined carbohydrates and little to no nutrients.

Replacing the seed oils in ultraprocessed foods with lard and beef tallow would make them even worse, Gardener adds.

The refining process of seed oils

Another claim is that “industrial seed oils,” as many critics call them, are “toxic” because they are highly processed. “It’s the idea that we take a seed, a natural thing, then we hyper-process it into (oil) and through that process, it becomes something that’s not good for our health,” says Wood.

However, there is no scientific evidence to support these claims, the experts say. “They’re not poison,” Wood adds.

The refining process can remove some nutrients, but it also makes the oil more heat-stable and less prone to oxidization, which can release harmful free radicals, or unstable molecules that may increase the risk of cancer, says Beal. Other vegetable oils also go through refining, as do some animal fats.

If you’re concerned about processing, the experts recommend first cutting out ultraprocessed foods.

What are animal fats?

Animal fats are lipids derived from animals, including beef, pork and poultry. Common animal fats include:

These fats are often rendered, which involves cooking the fat until it liquifies and can be separated from the meat. Animal fats may be refined to remove impurities and improve the smell or color, per the American Oil Chemists’ Society.

Butter is made by agitating milk cream to separate the liquid. Ghee, a staple in Indian cuisine, is butter that’s been clarified by cooking it to remove all the milk solids.

Animal fats are largely saturated fat, the experts note. “These are typically solid at room temperature,” says Beal. Some animal fats contain a small amount of monounsaturated fats, Beal adds.

Are animal fats healthy?

Animal fats, such as butter or tallow, aren’t exactly superfoods, but they may be healthy when eaten in moderation occasionally, as part of a healthy diet, the experts note.

The main issue is their high saturated fat content, which can raise “bad” LDL cholesterol. “Saturated fats are not beneficial in any way,” says Wood.

However, animal fats do have some positive qualities. They’re a good source of energy and rich in nutrients, such as fat-soluble vitamins, says Beal. These include vitamins A, D and E. “They also have stearic acid, which is beneficial,” Beal adds.

Animal fats tend to be more stable and add more flavor when cooking. “There’s a cultural element … and it’s a way to reduce food waste,” says Wood.

However, many nutrition experts say the risks of regularly eating animal fats outweigh the benefits. “The more saturated fat you eat, the more bad cholesterol you have in your blood, and that’s what leads to plaque, heart disease and strokes,” says Wood.

A 2024 study that followed over 407,000 people for 24 years found that a diet high in animal fat was associated with a higher risk of dying from any cause.

“We can eat some saturated fat, but when I say some, I mean a small amount,” says Beal. The AHA recommends limiting saturated fat to less than 6% of your total calories.

Is seed oil or animal fat healthier?

Seed oils are generally considered healthier than animal fats due to their high unsaturated fat content, which is linked to a number of benefits backed by research, according to the experts.

“There is a lot of evidence for the benefits of getting rid of saturated replacing it with polyunsaturated fats,” says Gardener.

Population studies show people who replace animal-based fats, such as butter or tallow, with seed oils tend to have a lower LDL cholesterol and lower rates of heart disease, Gardener says. “Your overall risk of mortality also goes down,” Wood adds.

However, it’s important to consider how you use the oil. The smoke point, or the temperature at which oil burns, is a big factor, says Beal.

The omega-6 fatty acids in seed oils can degrade and oxidize when heated to high temperatures, says Beal. “Oxidized fat is not good for you,” Wood adds. Burned oil should be tossed, and oils should never be re-used, the experts say.

Animal fat does not oxidize as rapidly at its smoke point as vegetable oils, but it can still burn and become rancid.

Moderation is also key, says Beal. The serving size of oil is small, just one tablespoon. “Cook with it, don’t drink it,” Gardener adds.

Although there’s no clear evidence to support using animal fat instead of seed oil, you don’t have to avoid animal fat entirely. “If you have a healthy diet full of nutritious foods and eat a little butter, you’ll be fine,” says Wood.

“Animal fat tastes really good, but I’m not trying to convince myself that it’s good for me,” Wood adds.

What is the healthiest oil to cook with?

Extra virgin olive oil or avocado oil are the healthiest cooking oils, the experts say. These are rich in heart-healthy monounsaturated fats, which help boost good cholesterol, and other nutrients.

Unrefined oil is better, says Beal, but has a lower smoke point. The experts suggest using different cooking oils for different purposes.

“If you’re frying or grilling, I’d say avocado or refined olive oil. For sautéing or baking, extra virgin olive oil. Then for salads or drizzling, I’d also use EVOO or another unrefined oil, like sunflower,” says Beal.

What is the healthiest animal fat?

If you’re going to cook with animal fat, Beal recommends opting for minimally processed fats from grass-fed, pasture-raised animals.

Grass-fed butter, for example, comes from cows that only eat grass, which leads to higher levels of heart-healthy omega-3 fatty acids and conjugated linoleic acid, TODAY.com previously reported.

Whether you use seed oils, animal fats or a combination, it’s important to have a balanced diet full of nutrient-dense, whole foods. “What you’re cooking with the oil is just as important,” says Gardener.

This article was originally published on TODAY.com