Are Seed Oils Really Bad? A Common-Sense Look at One of Nutrition's Most Heated Debates
- Jared C. Pistoia, ND
- 3 days ago
- 5 min read
The debate around seed oils is getting pretty intense. Some health influencers call them toxic, while others say they're fine to consume. Meanwhile, most of us are left wondering — what’s the truth? Are seed oils really bad? Or is this just another nutrition trend taken to extremes?
As a naturopathic doctor, I like to explore contentious nutrition topics using a common-sense approach rather than getting lost in data and "studies." If you go that route, you'll end up more confused.
As I approached this discussion, I first began to wonder how seed oils are made, how they're used, and when they were introduced to our diet. These are the basic questions I believe any curious person would ask.
So in this article, I’ll break down how seed oils are made, when they became popular, why they’re so controversial, and how to take a practical approach to fats and oils in your diet.
What Are Seed Oils — And How Are They Made?
Seed oils come from the industrial processing of crops like soybeans, corn, canola, cottonseed, sunflower, and safflower.
Unlike fruit-based oils such as olive oil or coconut oil, which can be pressed from their whole form, most seed oils require intense refining to become shelf-stable.
The process typically involves:
High heat
Mechanical pressing
Chemical solvents like hexane
Bleaching and deodorization
What’s left is a highly refined oil, often stripped of natural antioxidants and more prone to oxidation — especially when exposed to heat during cooking.
It's important to note that crops like soy, corn, rapeseed (canola) are some of the most commonly genetically modified (GMO) foods.
So, even after knowing just these facts, we have some major violations of what constitutes a health food.
Common seed oils include:
Soybean oil
Corn oil
Canola (rapeseed) oil
Cottonseed oil
Sunflower oil
Safflower oil
These oils now dominate the modern food supply — but that wasn’t always the case.
When Did Seed Oils Become Popular — And Why?
Seed oils didn’t exist in the human diet for most of history. They entered the food supply in the early 1900s, largely as a byproduct of industrial agriculture.
Companies realized they could take what was once considered waste — like cottonseed — and process it into inexpensive cooking oil.
The real tipping point came in the mid-20th century, when "health authorities" began promoting low-saturated-fat diets, which I consider to be a critical mistake. Butter and animal fats fell out of favor, and margarine—made from hydrogenated seed oils—became the new staple.
In the decades that followed, processed foods, fast food, and shelf-stable snacks — nearly all loaded with refined seed oils — exploded in popularity. Incidentally, margarine was discovered to be a big health risk.
To put it into perspective: Between 1909 and today, U.S. consumption of soybean oil alone has increased by over 1,000%.
Why Are Seed Oils Controversial?
From a scientific standpoint. the controversy about seed oil mostly boils down to one thing: omega-6 fats, which are abundant in seed oils.
Omega-6 fat is essential for health, just like omega-3. But the ratio of omega-6 and omega-3 fats is important in your body. Naturally, we tend to have higher omega-6 than omega-3 levels. A healthy ratio is thought to be between 1 : 1 and 4 : 1, respectively.
In other words, for every 4 molecules of omega-6, there should be at least 1 or more molecules of omega-3 in your body.
The issue is that the standard American diet is very high in omega-6 foods and very low in omega-3 foods. This is because most people consume high amounts of fried and processed foods, both of which contain high amounts of seed oils.
To make matters worse, most people under-consume omega-3 fats. The ratio gets disturbed and basically, this leads to inflammation.
Most people need less omega-6 and more omega-3. An easy way to check your levels would be to have a doctor order an omega-check. It shows your ratios clearly.
Excess omega-6 intake, especially from refined seed oils, has been linked to:
Increased inflammation
Disrupted cell membrane function
Greater oxidative stress
Some research has even explored potential links between seed oil-heavy diets and heart disease, metabolic dysfunction, and mood issues — though like many nutrition debates, the science is far from settled.
Are Seed Oils Really That Bad? A Common-Sense Perspective
It’s easy to fall into extremes — either avoiding seed oils like poison or dismissing the concerns entirely. The truth? As with most things in nutrition, it depends.
The Real Problem Isn’t Your Cooking Oil — It’s Hidden Seed Oils
The tablespoon of oil you cook your veggies in? Probably not the biggest concern. But the hidden seed oils in processed foods, restaurant meals, salad dressings, and snacks? That adds up fast.
Here’s a practical breakdown:
Industrial Seed Oils to Minimize:
Soybean oil
Corn oil
Cottonseed oil
Canola oil (especially when refined)
Better Choices (when cold-pressed and minimally processed):
Extra virgin olive oil (technically a fruit oil, but a superior option)
Cold-pressed flaxseed oil
Cold-pressed hemp seed oil
Small amounts of high-oleic sunflower oil
Small Daily Choices Shape Your Health — Especially for Your Gut
Whether it's hidden seed oils, processed foods., or everyday stress, these factors quietly chip away at your gut health — often without obvious symptoms at first.
But the good news? You have more control than you think. I created a simple, actionable tool to help you support your gut naturally — every single day.
👉 Download your free Gut-Healthy Daily Checklist and discover small, consistent habits that help reduce inflammation, support digestion, and create the foundation for long-term health.
What Are the Most Unhealthy and Healthiest Oils?
Most Unhealthy Oils:
Refined soybean, corn, cottonseed, and canola oils
Partially hydrogenated oils (found in some processed foods)
These oils are typically heat-processed, stripped of nutrients, and prone to oxidation — not ideal for long-term health.
Healthiest Oils (for most people):
Extra virgin olive oil
Cold-pressed coconut oil
Grass-fed butter or ghee (if tolerated)
Avocado oil
Cold-pressed flax or hemp seed oil (for cold use only)
As always, sourcing matters — the quality and processing of your oil is just as important as the type.
How to Avoid the Worst Offenders
Taking control of your fat intake doesn’t mean obsessing over every label. It means making small, sustainable shifts:
✔ Read ingredient labels — esp. dressings, chips, crackers, sauces, and frozen meals
✔ Cook at home with staple fats like olive oil, coconut oil, butter, tallow, or ghee
✔ Limit ultra-processed snacks, fast food, and fried food
✔ Don’t stress over occasional exposure — focus on consistent, long-term habits
The Bottom Line: Are Seed Oils Bad?
Seed oils are a modern addition to the human diet — one our biology may not be fully equipped to handle, especially in the quantities we consume today. But fear and extremes rarely lead to balanced health.
The practical takeaway?
Limit highly processed seed oils where you can
Focus on whole, unprocessed foods
Make changes that are realistic and sustainable
Most of your meals should be home-cooked
Because at the end of the day, real health comes from what you do consistently — not from chasing the latest nutrition panic.
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As a naturopathic physician, I believe that every person is unique—and so is their healing path. I take time to understand each patient’s story, physiology, emotional health, and lifestyle before making recommendations. Whether I’m using nutrition, herbal medicine, homeopathy, or lifestyle counseling, my goal is always the same: to identify and treat the true cause of illness so your body can restore balance on its own.
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