The Best Oils

The best oils are the ones that you make healthy meals with.

If you keep up with the news, you’ve read about the debate about seed oils. Some people claim that seed oils are unhealthy, even poisons, because they may be inflammatory. They advise using animal fat, or tallow, instead of seed oils. Longstanding science has said that healthy plant-based diets that include unsaturated fats, are healthy, lowering the risk of heart disease and other chronic diseases.

The seed oils that are said to be the most dangerous are soybean, canola (rapeseed), corn, grapeseed, cottonseed, safflower, rice bran, and sunflower. Other oils made from seeds include flaxseed, sesame, almond, and walnut.

There are studies that suggest that some of the seed oils can increase levels of inflammation in the body. Chronic low-grade inflammation does have harmful effects, including autoimmune disease, heart disease, and cancer. However, there are few, if any, well-designed studies that show these harms occur more in people who consume seed oils. Most studies suggesting harm are in animals and at high doses. Even cottonseed oil, which is rarely defended as healthy, doesn’t appear to increase inflammation.

Numerous well-designed studies show that overall, unsaturated fats derived from plants and their seeds lower the risk of heart disease compared to animal fats. Rather than quoting and referencing hundreds of articles, I reference this superb review. Of note, the authors discuss inflammation and oxidative stress (another proposed risk of seed oils) and show the strong evidence that plant oils are not a cause of these problems. This study from 2025 shows that plant oils, including canola and soybean, lower the risk of dying of heart disease or cancer. I could go on and on. Unsaturated fats from plants, including seed oils, have unsaturated fats and clearly benefit human health.

For those of you who really want to learn about the science of fat and inflammation, I refer you to this article. It describes that both unsaturated and saturated fats can sometimes increase inflammation under certain conditions, such as the other foods the person is consuming.

A big problem with studies on fats is that rarely does someone eat only the fat being studied. And even if they do, something else always changes. If you take people who are eating a lot of olive oil and substitute canola oil for it, you may see something negative. But the apparent harm could be from the removal of olive oil. Replacing tallow and lard with plant oils has shown significant benefit. Some could be from the plant oils, and some from not eating the saturated fat. Regardless, you are better off.

The most important factors are what you eat the oils with and how you prepare the food. Over the last several decades, we have been eating far more seed oil than in decades past. Those against these oils blame the oils themselves. I don’t entirely dismiss that possibility, but we’ve also been eating far more ultra-processed food (UPF), which now represents more than half of the calories consumed in the United States. We know ultra-processed food causes inflammation, heart disease, diabetes, obesity, and cancer. Eating the high-calorie, high-sugar UPF is the cause of these conditions, not the plant oil. I bet if you made Twinkies and jelly doughnuts with olive or flaxseed oil, two of the healthiest fats known, people would still become ill.

If the rest of your diet is healthy, unsaturated plant-based oils are better for your health than saturated fats from meat. That is why the Mediterranean Diet is so good for you. If you use olive oil every day, you are better off than if you use tallow every day. If you believe you have evidence from well-designed human studies to the contrary, please email me.

If you want to be healthy, eat mostly plant-based oil. If you’re afraid of seed oils, though I think they’re fine, you can cook exclusively olive oil and avocado oil, as I do. Use avocado for high heat, and olive oil for everything else. You shouldn’t cook with flaxseed oil, but I add it to yogurt. It’s very healthy and makes it creamier. If you want to be as healthy as possible, don’t eat ultra-processed foods, regardless of the oils they contain.

One final point. Robert F. Kennedy, the Health and Human Services secretary, is pleased that some fast food chains are using beef tallow to make their french fries. I don’t have strong feelings about what a restaurant does, but the main point should not be their frying oil. The more important thing for your health is not to eat french fries. We know that frying food isn’t healthy, and french fries have a high glycemic index. With the other foods served at fast food restaurants, you’ll gain weight. Read my book. If you follow the Three Rules, you’ll lose weight. If you also follow the Mediterranean diet, with or without seed oils, you will be even healthier.