Seed oils are vegetable oils extracted from the seeds of plants rather than from fruits (which is how oils like olive, avocado, and coconut are made). The most commonly discussed seed oils include canola, corn, cottonseed, grapeseed, rice bran, soybean, sunflower, and safflower oil. They're inexpensive, shelf-stable, and neutral-tasting, which is why they show up in everything from salad dressing to packaged snacks to restaurant fryers.
Why the Backlash?
The case against seed oils generally centers on three concerns:
- Omega-6 to omega-3 ratio. Seed oils are high in linoleic acid, an omega-6 fatty acid. Critics argue that a diet heavy in omega-6s relative to omega-3s may promote inflammation.
- Processing methods. Many seed oils are extracted using high heat and chemical solvents, which some argue could create byproducts worth scrutinizing.
- Correlation with the rise of processed food. Seed oils are ubiquitous in ultra-processed products, so critics point to the parallel rise of obesity and chronic disease rates alongside seed oil consumption over the past several decades.
This skepticism has gained serious cultural and political momentum. Public figures — most notably Robert F. Kennedy Jr. — have publicly criticized seed oils as one of the most harmful components of the modern American diet. That messaging has had real-world impact: recent U.S. dietary guidance updates have listed butter and beef tallow alongside olive oil as acceptable cooking fats, and several major food and restaurant companies have announced plans to phase seed oils out of their products.
What the Broader Research Community Says
Here's where it gets genuinely contentious: many nutrition scientists say the evidence doesn't back up the alarm.
The core argument in seed oils' defense is straightforward — when compared directly to saturated fats like butter or beef tallow, unsaturated fats (including those in seed oils) are consistently linked to lower LDL cholesterol, a well-established risk factor for cardiovascular disease. Some researchers who've spent careers studying this have said they're genuinely puzzled by where the "seed oils are bad" narrative originated, since it doesn't track with the clinical and observational data they've reviewed. Others note that seed oils, when used the way they're traditionally intended — in salad dressings or for light sautéing, rather than industrial deep frying — appear to be broadly beneficial rather than harmful.
There's also a pointed rebuttal to the "correlates with rising chronic disease" argument: seed oils are common in processed food, but that doesn't mean the oil itself is the harmful variable. Untangling seed oils from the ultra-processed, high-sugar, low-fiber foods they're usually found in is difficult, and some scientists argue the processed food itself — not the oil — is the more likely culprit.
It's also worth noting that funding sources cut both ways in this debate: some of the most prominent studies defending seed oils have industry backing, which is a legitimate point of scrutiny — just as some anti-seed-oil claims trace back to social media influencers rather than peer-reviewed research.
So, Where Does That Leave You?
Genuinely reasonable people — including credentialed nutrition scientists — disagree here, and both "camps" raise fair points worth sitting with:
If you're inclined to be cautious about seed oils: cutting back on ultra-processed, deep-fried food (regardless of which oil it's fried in) is a change most nutrition experts across the spectrum would support.
If you're inclined to trust the mainstream research: using seed oils in moderation for cooking — especially in place of butter, lard, or tallow — still has a substantial evidence base behind it for cardiovascular health.
Either way: the amount and type of food you're using any fat with likely matters more than the specific oil. Fries are still fries, whether they're cooked in canola oil or beef dripping.
The Bottom Line
The "seed oils" conversation has become as much a cultural and political flashpoint as a scientific one. If you want to make an informed choice for your own kitchen, it's worth looking past the headlines and influencer takes and considering: what's the rest of your plate look like? A tablespoon of sunflower oil in a stir-fry of vegetables is a very different equation than a plate of ultra-processed, deep-fried food — no matter which oil cooked it.
This article is for general informational purposes and isn't a substitute for personalized dietary advice from a registered dietitian or physician.