The Truth About Seed Oils

“Throw out your canola oil.”

“Never eat anything cooked in vegetable oil.”

“Seed oils are toxic.”

If you’ve been on Instagram, TikTok, or YouTube lately, you’ve probably seen these claims over and over again. It’s enough to make anyone question what’s in their kitchen.

As a registered dietitian, I get asked about seed oils all the time. And honestly? The answer isn’t nearly as dramatic as social media makes it seem.

Let’s separate the headlines from the science.

First, What Are Seed Oils?

Seed oils are exactly what they sound like—oils extracted from seeds. Common examples include:

• Canola oil
• Sunflower oil
• Safflower oil
• Soybean oil
• Corn oil
• Grapeseed oil
• Cottonseed oil

They’re used in home cooking, restaurants, packaged foods, salad dressings, sauces, and countless other products.

The reason they’ve become controversial is because they’re rich in omega-6 polyunsaturated fats, particularly linoleic acid. Some influencers claim these fats increase inflammation in the body and are responsible for today’s epidemic of obesity and chronic disease.

It sounds convincing.

The problem is…that’s not what the evidence shows.

Do Seed Oils Cause Inflammation?

This is probably the biggest myth.

For years, people have argued that eating more omega-6 fats creates inflammation because omega-6 fatty acids can be converted into compounds involved in the body’s inflammatory response.

But our bodies are much more complex than that.

Large reviews of human studies have consistently found that higher intakes of linoleic acid do not increase markers of inflammation in healthy adults. In fact, some studies have found the opposite—people who eat more polyunsaturated fats often have similar or even lower levels of inflammatory markers compared with those eating more saturated fat.

In other words, eating seed oils isn’t the same thing as pouring gasoline on inflammation.

What About Heart Health?

This is where the evidence becomes even stronger.

Replacing saturated fats like butter, lard, or shortening with unsaturated fats—including those found in many seed oils—has consistently been associated with lower LDL (“bad”) cholesterol and a lower risk of cardiovascular disease.

A large meta-analysis published in the Journal of the American Heart Association found that replacing saturated fat with polyunsaturated fat reduced cardiovascular events. That’s one reason organizations such as the American Heart Association continue to recommend replacing saturated fats with unsaturated fats as part of a heart-healthy eating pattern.

Heart disease remains the leading cause of death in the United States, accounting for nearly 1 in every 5 deaths each year according to the Centers for Disease Control and Prevention (CDC). That’s why focusing on evidence-based nutrition matters—not just the latest social media trend.

So Why Are People Blaming Seed Oils?

Here’s where things get confusing.

Many foods that contain seed oils are also highly processed.

Think about:

• French fries
• Potato chips
• Fast food
• Fried chicken
• Packaged pastries
• Cookies
• Snack crackers

But are these foods unhealthy because they contain canola oil?

Or because they’re often high in calories, refined carbohydrates, sodium, added sugars, and low in fiber?

Those are two very different questions.

Blaming seed oils alone ignores the bigger picture.

It’s a little like blaming the tires for a car accident instead of looking at the entire vehicle.

Should You Cook With Seed Oils?

For most people, yes.

Canola oil, for example, is low in saturated fat, contains heart-healthy unsaturated fats, and has a relatively high smoke point, making it practical for everyday cooking.

Olive oil is still my personal favorite for many meals because it’s rich in monounsaturated fats and has been extensively studied as part of the Mediterranean diet.

But that doesn’t mean canola oil or sunflower oil suddenly become “toxic.”

Instead of obsessing over one ingredient, focus on your overall eating pattern.

What Actually Matters More?

If you’re trying to improve your health, these habits will have a much bigger impact than eliminating seed oils:

• Eating more vegetables and fruit
• Getting enough protein
• Choosing high-fiber foods
• Strength training regularly
• Sleeping 7–9 hours most nights
• Managing stress
• Limiting ultra-processed foods overall
• Cooking more meals at home

Those are the habits supported by decades of research—not viral videos.

My Take as a Dietitian

Nutrition has a way of swinging from one extreme to another.

One year it’s eggs.

The next it’s gluten.

Then carbs.

Now it’s seed oils.

The truth is that nutrition is rarely black and white.

If your diet is mostly made up of lean proteins, vegetables, fruit, whole grains, healthy fats, and foods you genuinely enjoy, I’m not worried about the tablespoon of canola oil you used to roast your vegetables.

I’d spend far more time helping you eat enough protein, build muscle, improve your blood sugar, and create habits you can actually stick with.

Because that’s what makes the biggest difference over time.

The Bottom Line

You don’t need to fear seed oils.

Current research does not support the idea that seed oils are inherently inflammatory or toxic when consumed as part of a balanced diet. What matters far more is your overall eating pattern, your activity level, and the lifestyle habits you repeat every day.

If nutrition headlines have you wondering what to believe, you don’t have to sort through the noise alone. At RYS Nutrition, I help people cut through nutrition myths with science-based advice that fits real life—not social media trends. Whether your goal is weight loss, better cholesterol, diabetes prevention, sports performance, or simply feeling healthier, we’ll create a plan that’s practical and sustainable.

And if you’re ready to put that nutrition plan into action, join us at Isaiah 40:31 Fitness. Our welcoming community and strength-focused classes are designed for every fitness level, because eating well and moving well are a powerful combination.

Stop chasing nutrition fads. Start building habits that last. Schedule an appointment with RYS Nutrition or come try a class at Isaiah 40:31 Fitness—we’d love to help you reach your goals.