If you've spent any time on health Twitter or TikTok in the last couple of years, you've probably seen people talking about seed oils. Maybe you've seen someone refuse a meal because it was cooked in canola oil. Maybe you've seen the "hateful eight" list floating around. Maybe you've just thought: why are people suddenly against seed oils?
Fair question. Let's actually break it down — no scare tactics, no pseudoscience, just what we know and what it means for the food you eat every day.
So, What Are Seed Oils?
Seed oils are exactly what they sound like: oils extracted from the seeds of plants. The tricky part is that the food industry usually labels them as "vegetable oils" — which sounds healthy, but these aren't oils pressed from broccoli or spinach. They're industrially processed oils made from seeds like soybeans, corn, canola (rapeseed), sunflower, safflower, cottonseed, grapeseed, and rice bran.
If you're wondering what oils are considered seed oils, here's the list that people in this space commonly reference:
- Soybean oil — the most widely consumed oil in the U.S.
- Canola oil (rapeseed) — marketed as "heart healthy" for decades
- Corn oil
- Sunflower oil
- Safflower oil
- Cottonseed oil
- Grapeseed oil
- Rice bran oil
These eight are sometimes called the "hateful eight" seed oils or the "hateful eight oils list." You'll also hear people ask about "the 7 seed oils" or "the 7 bad oils" — it varies because some lists drop one (usually rice bran), but the core group is the same.
And yes — Crisco is considered a seed oil product. It's made from partially hydrogenated soybean and palm oils. It was literally one of the first mainstream seed oil products in American kitchens.
Is Olive Oil a Seed Oil?
No. This is one of the most common questions and the answer is simple: olive oil is not a seed oil. It's pressed from the fruit of the olive, not from a seed. Same goes for avocado oil and coconut oil — they're fruit or nut oils, and they've been used in traditional cooking for centuries. Seed oils, by contrast, only became widespread in the early-to-mid 1900s thanks to industrial processing.
What Is the Problem with Seed Oils?
Here's where it gets interesting. The main concern comes down to three things:
1. Omega-6 Fatty Acids Are Wildly Out of Balance
Your body needs both omega-3 and omega-6 fatty acids. The issue is ratio. For most of human history, people ate omega-6 and omega-3 in roughly a 1:1 to 4:1 ratio. Today, the average American diet is somewhere around 20:1 — almost entirely because of seed oils. Seed oils and omega-6 fatty acids are essentially inseparable; these oils are the single largest source of omega-6 in the modern diet.
When omega-6 is that dominant, it competes with omega-3 for the same metabolic pathways. The result? More inflammatory compounds, less anti-inflammatory ones. Your body is literally tipped toward chronic low-grade inflammation.
2. Are Seed Oils Inflammatory?
The short answer: the evidence strongly suggests yes. The linoleic acid in seed oils gets converted into arachidonic acid, which is a precursor to pro-inflammatory signaling molecules. When you're eating seed oils at every meal — which most people are, because it's in everything from salad dressings to "healthy" granola — you're flooding your system with inflammatory precursors.
This doesn't mean you'll feel inflamed overnight. It's a slow burn (no pun intended). But researchers have been connecting chronic inflammation to conditions like metabolic syndrome, autoimmune issues, and yes, seed oils and heart disease are a conversation that's gaining traction in nutrition research. The old assumption that seed oils are "heart healthy" because they lower LDL cholesterol is being challenged, because LDL alone doesn't tell the full story.
3. How They're Made Is Concerning
Unlike olive oil, which you can literally squeeze out of an olive, seed oils require an industrial extraction process involving high heat, chemical solvents (usually hexane), and deodorizing. By the time the oil reaches your bottle, it's been through a process that would make most people uncomfortable if they saw it. The seed oil nutritional profile that makes it to your plate has been stripped and altered from what the original seed contained.
Are Seed Oils Bad for You? What the Research Says
Let's be honest: the science is still evolving. There are studies on both sides. The mainstream nutrition establishment still largely says seed oils are fine, pointing to short-term studies on LDL cholesterol. But a growing body of research — and a growing number of doctors and researchers — are questioning that position.
What we do know:
- Omega-6 consumption from seed oils has increased dramatically over the past century, in lockstep with rates of obesity, heart disease, and metabolic issues.
- Linoleic acid (the primary fat in seed oils) accumulates in body fat and cell membranes over time.
- Multiple studies link high linoleic acid intake with increased oxidative stress.
- The healthiest traditional diets around the world — Mediterranean, Japanese, ancestral — don't use seed oils.
Is this proof of causation? No. But the pattern is hard to ignore, and the precautionary principle applies: if there's a reasonable chance these oils are contributing to chronic disease, and there are better alternatives available, why not switch?
What Are the Worst Seed Oils to Avoid?
If you're trying to clean up your diet, here's a complete list of seed oils to avoid, ranked by how common they are in processed food:
- Soybean oil — in roughly 70% of processed foods in the U.S.
- Canola oil — the default "cooking oil" at most restaurants
- Corn oil — common in fried foods and snacks
- Sunflower oil — increasingly marketed as a "premium" alternative
- Cottonseed oil — originally an industrial waste product
- Safflower oil
- Grapeseed oil — often found in "health food" products
- Rice bran oil — common in Asian fast food
These are the six (or eight) seed oils to avoid depending on which list you follow. The principle is the same: if it required an industrial process to extract, be skeptical.
Seed Oil vs Olive Oil: What's Actually Different?
Comparing seed oil vs olive oil is really comparing two totally different products. Extra virgin olive oil is cold-pressed from whole olives, retains its polyphenols and antioxidants, is primarily monounsaturated fat (oleic acid), and has been used for thousands of years. Seed oils are industrially extracted, high in polyunsaturated omega-6 fats, stripped of nutrients during processing, and became common only in the last 100 years.
If you're asking what is the healthiest oil to cook with, most people in this space would say:
- Extra virgin olive oil — for lower-heat cooking, dressings, and finishing
- Beef tallow — excellent for high-heat frying (this is what Five Guys and many of our listed restaurants use)
- Butter / ghee — great all-purpose cooking fats
- Coconut oil — good for baking and medium-heat cooking
- Avocado oil — high smoke point, neutral flavor
These are the best seed oil alternatives — traditional fats that humans have been using for centuries, long before chronic disease rates started climbing.
And what is the unhealthiest oil? By most of the criteria above, soybean oil takes that spot. It's the most consumed, the most processed, and the most researched in terms of negative metabolic effects. If there's one unhealthiest cooking oil to drop first, that's the one.
What Oil Do Cardiologists Recommend?
This depends on the cardiologist. The conventional answer has been canola and soybean oil, based on their LDL-lowering effects. But a growing number of cardiologists — and health educators we feature on our site — now recommend extra virgin olive oil as the gold standard, with animal fats like tallow and butter making a comeback in clinical conversations. The tide is turning, even if the official guidelines haven't caught up yet.
Are Seed Oils Banned in Europe?
Not exactly. You'll see the claim that seed oils are banned in Europe online, but the reality is more nuanced. Europe hasn't banned seed oils outright. However, several European countries have stricter regulations around trans fats (which often come from partially hydrogenated seed oils), and the cultural default in countries like Italy, Greece, and Spain is olive oil — not canola. European diets tend to use far less seed oil per capita, which tracks with lower rates of obesity and metabolic disease. So it's not a ban, but the practical effect is similar: people eat a lot less of it.
What Happens When You Stop Eating Seed Oils?
People report all kinds of things: less bloating, clearer skin, reduced joint pain, better digestion, more stable energy. Anecdotal? Yes. But when thousands of people report similar changes, it's worth paying attention.
The biological logic tracks too. When you remove the primary source of excess omega-6 from your diet, your omega-6 to omega-3 ratio starts to normalize. Less inflammatory signaling, less oxidative stress. It won't happen in a week — linoleic acid stored in your fat tissue takes months to turn over — but most people notice meaningful changes within 30 to 90 days.
The Bottom Line
Are seed oils the sole cause of modern chronic disease? No. But they're a massive, under-discussed piece of the puzzle. They've only been part of the human diet for about a century, they're in nearly every processed food, and the science around omega-6 overload is hard to dismiss.
The good news? Avoiding them is getting easier. More restaurants are cooking with tallow, butter, and olive oil. More brands are going seed-oil-free. And directories like ours make it simple to find them.
Ready to eat out clean? Check out our guide on how to eat out without seed oils, or browse our seed-oil-free restaurant directory to find options near you.