Are Seed Oils Bad for You? A Nutrition Consultant Explains

Seed oils might be the most divisive topic in wellness right now. They’ve been called toxic, inflammatory, and the driving force behind chronic disease. But is any of that actually supported by research? As a nutrition consultant (and mom of two), I’ve been fielding this question constantly in my coaching calls, and the confusion is completely understandable. The conversation has gotten loud and very political. So I decided to break the whole thing down in my latest podcast episode, and in this article, I’m giving you the full picture so you can make decisions from a place of confidence, not fear.

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What are Seed Oils?

Seed oils are cooking oils extracted from the seeds of plants. The 8 that get the most attention online have been nicknamed the “Hateful 8” (dramatic, I know). Those are: canola, corn, cottonseed, soybean, sunflower, safflower, grapeseed, and rice bran oil. If you’ve looked at the ingredient list on a bag of chips, box of crackers, a jar of mayo, or a bottle of salad dressing, there’s a very good chance you’ve seen at least one of these. They’re widely used in packaged foods and restaurant kitchens because they’re affordable, have a neutral flavor, and hold up well at high cooking temperatures. From a food manufacturing standpoint, they check every box.

How are Seed Oils Made?

Most seed oils are extracted using a combination of heat and chemical solvents, the most common being hexane. And I understand why that makes people uncomfortable. But the trace amounts that remain in refined oils are extremely small (parts per million). So long as you aren’t consuming them frequently, there’s no reason to panic. Rest assured, “processed with hexane” and “dangerous to consume” are not the same statement.

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Why the Seed Oil Debate Has Gotten So Heated

Before we get into the science, it’s worth acknowledging why this topic has exploded. Seed oils have become a cultural flashpoint. The new 2026 Dietary Guidelines for Americans recommended olive oil, butter, and beef tallow for cooking, and Robert F. Kennedy Jr. has publicly criticized seed oils as a driver of obesity. That gave the anti-seed oil movement a massive signal boost.

But here’s the thing: the scientific community has largely pushed back on that framing. Researchers at Johns Hopkins, Stanford, and the American Heart Association have all been clear that the evidence doesn’t support the idea that seed oils are a primary cause of chronic disease. So what you’re seeing online is a collision between politics and nutrition science, and that’s exactly why it’s so confusing to navigate as a consumer.

I get much deeper into this in the podcast e pisode, including what the new guidelines got right and where I think they went off track.

Are Seed Oils Inflammatory? What the Research Says

This is the biggest claim against seed oils: that they’re high in omega-6 fatty acids (specifically linoleic acid), which cause inflammation, which leads to heart disease, diabetes, cancer, and everything else. Parts of that chain are technically true. Seed oils are high in omega-6 fatty acids. And omega-6s do play a role in the body’s inflammatory response. But the conclusion that omega-6s are inherently inflammatory is a misunderstanding of how these fatty acids actually work.

Understanding Omega-3 Fatty Acids

Omega-6 fatty acids are essential fatty acids. Your body can’t produce them on its own, so you need to get them from food. They support brain function, heart function, cell growth, and development. The idea that they’re “pro-inflammatory” comes from the oversimplification that because omega-3s are anti-inflammatory, omega-6s must be the opposite. Researchers at Stanford and Johns Hopkins have been very clear that both play a role in the inflammatory response and both are necessary.

Taking a Closer Look at the Data

A research team at Johns Hopkins found that people with the highest levels of linoleic acid had a 35% lower risk of developing type 2 diabetes compared to those with the lowest levels (Marklund et al., Lancet Diabetes & Endocrinology). And when they looked at cardiovascular disease, the protective association held regardless of whether participants had high or low omega-3 levels.

A 2017 meta-analysis of randomized controlled trials found that increased linoleic acid intake had no significant effect on blood concentrations of inflammatory markers. And a 2023 review in the International Journal of Molecular Sciences found that higher omega-6 intake was associated with better cardiovascular health and improved glucose metabolism.

So the central claim of the anti-seed oil movement, that these oils drive inflammation, is not well supported by the human evidence we have. That’s not me being dismissive. That’s what the research shows.

The Omega-6 to Omega-3 Ratio: Does It Actually Matter?

The second argument you hear often is about the ratio. Historically, humans ate a diet with roughly a 1:1 ratio of omega-6 to omega-3 fatty acids. In the standard American diet today, that ratio has shifted to somewhere around 10:1 or even 20:1 in favor of omega-6. The claim is that this imbalance is driving disease. The idea of a ratio imbalance isn’t unreasonable, but the research doesn’t support the conclusion that the ratio itself is the problem! What researchers consistently recommend is this: instead of reducing your omega-6 intake to fix the ratio, increase your omega-3 intake (eat more walnuts, more fatty fish, etc).

And here’s something people don’t talk about enough: canola oil, which is literally one of the “Hateful 8,” has one of the lowest ratios of omega-6 to omega-3 of any common dietary fat. Even within the seed oil category, the picture is far more nuanced than the internet makes it seem.

Do Seed Oils Produce Toxic Compounds When Heated?

This is the argument I think has the most nuance, and I want to be honest about that. When any oil is heated to high temperatures, especially during deep frying, chemical reactions happen. Oxidation occurs. And that oxidation can produce compounds called aldehydes, some of which are not great for you.

But the dose matters. The temperature matters. How long you’re heating the oil matters. Whether you’re reusing it matters. The research on aldehyde formation is primarily focused on deep frying at extremely high temperatures for extended periods, like what happens at a fast food restaurant cycling through the same oil for hours. That is a very different scenario from drizzling sunflower oil on a sheet pan of roasted broccoli at 400 degrees.

If you want to optimize, using oils that are higher in monounsaturated fats for higher-heat cooking (olive oil, avocado oil) is a smart, evidence-based move.

The Real Problem Nobody Talks About

Here’s where I really want you to zoom out, because I think the seed oil debate misses the forest for the trees. The issue isn’t the oil. It’s what the oil is in. Seed oils show up most heavily in ultra-processed foods: chips, crackers, fast food, packaged baked goods, frozen meals. Those foods are also loaded with added sugars, refined carbs, sodium, and artificial ingredients, and they’re generally low in nutrients. So when a study associates higher seed oil consumption with worse health outcomes, you have to ask: Is it the oil? Or is it the overall dietary pattern?

This is what nutrition researchers keep emphasizing. You can’t isolate the seed oil from the context it’s consumed in. One ingredient will never matter more than the overall way you eat.

This is also why I built The Strong(er) Body Blueprint. It’s not about perfecting every single ingredient. It’s about building a nutrition foundation that supports your goals, whether that’s body recomposition, more energy, or just feeling stronger in your own skin.

What Oils Should You Cook With?

So what does a nutrition consultant actually use in her kitchen? Here’s what I reach for:

Extra virgin olive oil is my go-to for most cooking. Roasting vegetables (under 400F), salad dressings, and sauteing. The research on olive oil and cardiovascular health is strong, and it’s a cornerstone of the Mediterranean diet, one of the most well-studied dietary patterns we have.
Avocado oil (or avocado oil spray) is what I use for higher-heat cooking like searing, stir-frying, or roasting veggies above 400F. It has a high smoke point and is rich in monounsaturated fat, so it holds up well.
Butter and ghee have a place in our house too! Baking, toast, and eggs, mainly.

And do I avoid seed oils? No. If I’m at a restaurant and they cooked my food in canola oil, I’m not going to stress about it. If my kids have crackers with sunflower oil on the label, I’m not panicking. Because the dose matters, the frequency matters, the overall dietary pattern matters, and the stress you put on yourself about food? That matters too. Chronic stress is more damaging to your body than a tablespoon of canola oil.

What to Take Away from the Seed Oil Debate

Seed oils aren’t the villain the internet has made them out to be. The human evidence we have does not support the claim that consuming seed oils in normal amounts causes inflammation or chronic disease. The real issue is ultra-processed food, not the oil itself. Reducing your intake of ultra-processed food and eating more whole foods will move the needle far more than obsessing over which oil is in your pantry.

If you want to optimize your cooking oils, use extra virgin olive oil as your everyday go-to, avocado oil for high heat, and prioritize omega-3-rich foods like fatty fish, walnuts, and flaxseed.

Listen to the Full Episode

I go much deeper into all of this in my latest podcast episode, including the specific studies I referenced, my thoughts on the new dietary guidelines, and why the omega-6 “inflammation” narrative fell apart under scrutiny. If you’ve been confused or stressed about seed oils, this episode will help you feel a whole lot calmer. Listen here! Last but not least, be careful about where you get your nutrition information. The seed oil conversation has become incredibly politicized. When someone tells you to be afraid of a food, always ask: what are they selling? What’s the alternative they’re pushing? Who benefits? In my years of health coaching, the truth in nutrition is almost always more nuanced and less scary than the headline. And that is definitely the case here.