Scroll through TikTok or listen to wellness podcasts, and you’ll hear that eight common cooking oils dubbed the “Hateful Eight” are destroying your health, causing everything from obesity to cancer. The hashtag #seedoils has accumulated over 126 million views.

Apps like Seed Oil Scout, which maps restaurants that don’t use these oils, have been downloaded nearly 2 million times. And when Health Secretary Robert F. Kennedy Jr. declared that Americans are being “unknowingly poisoned” by vegetable oils, the controversy moved from fringe wellness circles into mainstream political discourse.

The thing: you’re probably confused. On one hand, wellness influencers insist these oils are toxic. On the other, the American Heart Association and major medical institutions have spent decades recommending vegetable oils over animal fats for heart health. Who’s right?

What Is the Seed Oil Controversy? The Rise of the “Hateful Eight”

The term “Hateful Eight” refers to eight specific seed oils that critics claim are damaging human health: canola, corn, cottonseed, soy, sunflower, safflower, grapeseed, and rice bran. The phrase was popularized by Dr. Cate Shanahan, a Cornell-trained physician and author, who argues that these industrially-processed oils are responsible for a wide range of modern health problems.

The controversy itself isn’t entirely new nutrition researcher Ray Peat raised concerns about polyunsaturated fats in the 1970s but it exploded into mainstream awareness around 2020. That’s when podcaster Joe Rogan interviewed Paul Saladino, a carnivore diet advocate who made sweeping claims about the health effects of vegetable fats.

Since then, the message has spread rapidly through wellness influencers, biohacker communities, and eventually into political discourse when Kennedy made it a central theme of his “Make America Healthy Again” campaign in 2024.

The core claims are straightforward: seed oils contain high levels of omega-6 fatty acids, particularly linoleic acid. Critics argue that when you eat these fats, your body converts them into arachidonic acid, which produces inflammatory compounds.

This chronic inflammation, they say, drives obesity, heart disease, diabetes, and even cancer. Some influencers go further, claiming that the industrial processing of these oils which often involves heat, chemical solvents like hexane, and refining steps creates toxic byproducts.

Why does this message resonate so strongly? Several factors are at play. There’s legitimate distrust of processed foods and the industrial food system. There’s appeal in “returning to traditional eating” the idea that our ancestors ate butter and lard, and therefore so should we. And there’s the simple power of a clear villain. As Dr. Dariush Mozaffarian, director of the Food Is Medicine Institute at Tufts University, observed, “People love a black hat versus a white hat, a bad guy versus a good guy.”

The scale of this movement is significant. According to Purdue University’s Consumer Food Insights Report from April 2025, 20% of Americans are now actively trying to avoid seed oils in their cooking up from 18% just a year earlier.

More than half of consumers (55%) encounter information about seed oils on social media, which they generally rank as less trustworthy than healthcare professionals but are exposed to far more frequently. As the researchers noted, “the constant messaging of social media influencers could be drowning out more informed voices.”

But popularity doesn’t equal accuracy. And when you look at what major research institutions and decades of clinical trials actually show, a very different picture emerges.

The Evidence on Seed Oils: What Do Major Studies Actually Show?

Let’s start with the largest and most recent evidence. In March 2025, the Journal of Translational Medicine published a massive meta-analysis examining 150 publications on omega-6 fatty acids and health outcomes.

The findings directly contradicted the influencer narrative: higher dietary intake and circulating levels of omega-6 were associated with lower risks of cardiovascular disease, cancer incidence, and all-cause mortality. The protective associations were particularly strong for coronary heart disease and stroke.

This isn’t an outlier finding. The American Heart Association has consistently supported omega-6 fatty acid consumption as part of a healthy diet and has explicitly warned against reducing intake. Their position is based on decades of research showing that polyunsaturated fats from plant sources help reduce LDL (“bad”) cholesterol, which in turn lowers cardiovascular risk.

A global consortium study published in Circulation, examining data from 30 prospective studies across 13 countries, found that higher levels of linoleic acid—the primary omega-6 in seed oils—were associated with significantly lower risks of total cardiovascular disease, cardiovascular mortality, and ischemic stroke. Specifically, participants with higher linoleic acid levels had a 22% lower risk of dying from cardiovascular causes compared to those with lower levels.

Dr. Christopher Gardner, director of nutrition studies at the Stanford Prevention Research Center and a member of the 2025 Dietary Guidelines Advisory Committee, puts it bluntly: “There are actually few associations in nutrition that have this much evidence behind them.”

He notes that every study for decades has shown that replacing saturated fat with unsaturated fat lowers LDL cholesterol—a finding that has been “reaffirmed again and again.”

What about diabetes? Dr. Matti Marklund, an assistant professor at Johns Hopkins Bloomberg School of Public Health who researches how dietary fats affect chronic disease, found that participants with the highest levels of linoleic acid had a 35% lower risk of developing type 2 diabetes compared to those with the lowest levels.

His research also shows that linoleic acid improves glucose metabolism directly contradicting claims that seed oils contribute to metabolic dysfunction.

Do Seed Oils Really Cause Inflammation? The Omega-6 Misunderstanding

The inflammation argument is the cornerstone of the anti-seed-oil case, and it sounds scientifically plausible at first. The logic goes like this: Omega-3 fatty acids (found in fish, flax, and walnuts) are anti-inflammatory. Omega-6 fatty acids (abundant in seed oils) must therefore be pro-inflammatory. Since Americans eat far more omega-6 than omega-3—some estimates suggest a ratio of 10:1 or higher—we must be swimming in chronic inflammation.

Yes, linoleic acid can be converted to arachidonic acid in the body, and arachidonic acid is a precursor to some inflammatory compounds. But what the influencer crowd conveniently omits: only about 0.2% of dietary linoleic acid actually gets converted to arachidonic acid in humans.

The conversion is tightly regulated by enzymes. More importantly, arachidonic acid is also a precursor for compounds that fight inflammation. The body uses these pathways for healing—inflammation in response to injury or infection is supposed to happen. The question is whether dietary omega-6 intake causes the kind of chronic, problematic inflammation linked to disease.

The research says it doesn’t.

A systematic review published in the Journal of the Academy of Nutrition and Dietetics examined randomized controlled trials specifically designed to test whether dietary linoleic acid affects inflammatory markers in healthy people. The conclusion: there was “virtually no evidence” that adding linoleic acid to the diet increases inflammatory biomarkers.

A 2017 meta-analysis of 30 randomized controlled studies involving 1,377 subjects reached the same conclusion—no significant effect of higher linoleic acid intake on C-reactive protein, interleukin-6, tumor necrosis factor, or other standard markers of inflammation.

The most recent research reinforces these findings. A June 2025 study published in Nutrients, examining data from the Framingham Heart Study (one of the longest-running heart disease studies in history), found significant inverse associations between red blood cell linoleic acid levels and inflammatory biomarkers. Translation: higher omega-6 levels in the body were associated with lower inflammation, not higher.

Dr. William Harris, president of the Fatty Acid Research Institute and one of the study authors, challenges the conventional framing: “The problem is not the omega-6. It’s the lack of the omega-3 that is ‘out of balance.'” Rather than omega-6 being inflammatory, the issue—if there is one—is that people don’t eat enough omega-3s. The solution isn’t eliminating seed oils; it’s eating more fatty fish, walnuts, and flaxseed.

Ultra-Processed Foods, Not Seed Oils: Where the Blame Really Belongs

What the seed oil critics get right: there is a genuine health crisis, and the modern American diet is driving it. Where they go wrong is in identifying the culprit.

Seed oils are found in virtually all ultra-processed foods—from chips and frozen dinners to packaged cookies and fast food. But correlation isn’t causation, and blaming the oil while ignoring everything else in those products is like blaming the steering wheel for a car crash caused by drunk driving.

Consider what ultra-processed foods actually contain: excessive added sugars, high levels of sodium, refined carbohydrates stripped of fiber and nutrients, artificial additives, emulsifiers, and often multiple ingredients designed in laboratories to be hyper-palatable.

A 2024 review published in The BMJ examined 45 analyses involving roughly 10 million people and identified 32 health problems linked to ultra-processed food consumption—including premature death, cardiovascular disease, obesity, type 2 diabetes, depression, and sleep disorders.

Research from the University of Texas at Austin found that for people with type 2 diabetes, eating more ultra-processed foods was associated with higher blood sugar levels—but this effect couldn’t be explained by sugar or sodium content alone. The researchers concluded that synthetic flavors, artificial sweeteners, emulsifiers, and other additives may be partly responsible, suggesting something beyond basic nutrients is causing harm.

A study published in The Lancet Regional Health – Europe followed over 300,000 people across eight European countries and found that every 10% increase in ultra-processed food consumption was associated with a 17% higher risk of developing type 2 diabetes. Crucially, replacing ultra-processed foods with less processed alternatives reduced this risk.

The Truth About Cooking with Oils: Why Smoke Point Isn’t Everything

Walk into any kitchen conversation about cooking oils, and someone will inevitably bring up smoke point—the temperature at which an oil begins to smoke and break down. The conventional wisdom is straightforward: for high-heat cooking, use oils with high smoke points. This has led many people to choose refined vegetable oils over olive oil for frying and sautéing.

But this advice is outdated, and the reason why reveals something important about how we evaluate cooking fats.

Smoke point measures one thing: when an oil starts producing visible smoke. It doesn’t measure what happens chemically when you cook with that oil—specifically, how stable it remains and whether it produces harmful compounds. For that, you need to look at oxidative stability.

A 2018 study published in Acta Scientific Nutritional Health put this to the test. Researchers heated ten common cooking oils to high temperatures (464°F) and monitored what happened. They also tested the oils in deep-fryer conditions at 356°F for six hours. The results surprised many people in the culinary world: extra virgin olive oil demonstrated superior stability, producing the lowest levels of harmful polar compounds and oxidative byproducts.

Meanwhile, oils with higher smoke points—including canola, sunflower, grapeseed, and rice bran oil produced more harmful compounds despite theoretically being “better” for high-heat cooking. The reason? These oils are high in polyunsaturated fats, which are chemically less stable when heated. Extra virgin olive oil, despite its moderate smoke point, is rich in monounsaturated fats and natural antioxidants (like polyphenols) that resist oxidation.

The North American Olive Oil Association summarizes the research this way: “Smoke point does not correlate with performance and stability when heated. Rather, the factors that predict an oil’s safety and stability at high heat are the percentage of polyunsaturated fats (the lower the better), and the extent to which the oil has been refined (the less the better).”

What the Mediterranean Diet Teaches Us About Heart-Healthy Oils

Rather than obsessing over what to avoid, it’s worth examining what actually works. And for cardiovascular health, no dietary pattern has more robust evidence than the Mediterranean diet—which centers on a very particular fat: extra virgin olive oil.

The landmark PREDIMED trial, one of the largest and most rigorous dietary intervention studies ever conducted, followed 7,447 people at high cardiovascular risk across Spain for nearly five years. Participants were randomly assigned to either a Mediterranean diet supplemented with extra virgin olive oil, a Mediterranean diet supplemented with nuts, or a control diet (advised to reduce fat).

The results, published in the New England Journal of Medicine, were striking: both Mediterranean diet groups experienced approximately 30% fewer major cardiovascular events (heart attacks, strokes, or cardiovascular death) compared to the control group.

The PREDIMED trial didn’t just show that Mediterranean eating is healthy—it specifically demonstrated the benefits of generous olive oil consumption. Participants in the olive oil group consumed about four tablespoons daily.

More recent research has expanded these findings. The PREDIMAR study, presented at Heart Rhythm 2024, found that patients with atrial fibrillation who followed a Mediterranean diet enriched with extra virgin olive oil after ablation procedures had better outcomes than those who freely selected their diet.

Your 2025 Guide to Choosing the Right Cooking Oil

So what should actually be in your pantry? After reviewing the evidence, a practical framework not based on TikTok trends or political talking points, but on what research supports.

Your everyday workhorse: Extra virgin olive oil. Despite persistent myths, olive oil is excellent for most cooking applications including sautéing, roasting, and yes, even pan-frying at normal temperatures. It’s stable under heat, rich in beneficial compounds, and backed by the strongest evidence for cardiovascular benefits. Use it for dressings, drizzling, and most stovetop cooking. Don’t buy into the myth that it can’t handle heat.

For very high heat: Avocado oil. If you’re deep-frying or cooking at temperatures above 400°F, avocado oil offers a high smoke point (around 520°F) with a nutritional profile similar to olive oil high in monounsaturated fats and relatively low in polyunsaturated fats. It has a neutral flavor that works in various cuisines.

Seed oils: Not the enemy, but not special either. Canola, sunflower, and other seed oils are fine for occasional use in home cooking. They’re not poisoning you, and they’re significantly better for your heart than butter or lard. If a recipe calls for vegetable oil or you want something more affordable and neutral-tasting for certain dishes, use them without guilt. What you shouldn’t do is treat them as health foods or use them in the context of eating lots of ultra-processed foods.

What to actually limit: Repeatedly reheated oils (don’t keep that frying oil forever), excessive fried foods (whether cooked in seed oil or tallow), and ultra-processed foods in general. The problem has never really been about which oil; it’s about how much processed and fried food we eat.

Conclusion

The seed oil controversy reveals something important about nutrition information in 2025: compelling narratives spread faster than nuanced evidence. The idea that eight specific oils are “poisoning” America is emotionally satisfying, assigns clear blame, and offers a simple solution. It’s also not supported by the weight of scientific research.

Major meta-analyses consistently show that omega-6 fatty acids are associated with lower not higher cardiovascular disease risk and mortality. Randomized controlled trials find no meaningful effect of linoleic acid on inflammatory markers. The American Heart Association explicitly supports including these fats as part of a healthy diet. Meanwhile, the real driver of diet-related disease ultra-processed food consumption often gets overshadowed by the seed oil panic.