For years, we've been told to ditch saturated fats and cook with vegetable oils instead. You’ve probably heard the advice: “Use heart-healthy oils like canola or sunflower instead of butter.” But what if that advice was based on outdated science—and may even be contributing to rising rates of chronic disease?

Recent research is challenging everything we thought we knew about fat. A paper published in Frontiers in Nutrition proposes that refined, bleached, and deodorized (RBD) seed oils—like soybean, canola, corn, cottonseed, sunflower, and safflower oil—may be major drivers of insulin resistance, type 2 diabetes, and even cancer.

Let’s unpack what this means, and why Functional Medicine practitioners are paying attention.

What Are Seed Oils?

Seed oils are a type of vegetable oil extracted from the seeds of plants. Sounds healthy, right? But what’s often missing from the conversation is how these oils are made.

To produce them, manufacturers use industrial processes involving high heat, chemical solvents (like hexane), bleaching agents, and deodorizing techniques. The end result: a clear, odorless, shelf-stable oil rich in polyunsaturated fatty acids (PUFAs)—mainly linoleic acid.

Unfortunately, this heavy processing also leaves behind a toxic footprint in the body.

The New Theory: How Seed Oils May Disrupt Your Health

According to this paper, consuming large quantities of RBD seed oils can lead to:

• Oxidative Stress in Your Cells

These oils get incorporated into your cell membranes and body fat, making them more vulnerable to oxidative damage. That’s like rust forming inside your cells—damage that ages tissues and impairs function.

• Mitochondrial Dysfunction

Your mitochondria—the tiny engines inside your cells—struggle when overwhelmed by these fragile fats. They stop burning fat efficiently, pushing the body to rely more on glucose for energy instead.

This shift is known as aerobic glycolysis and is a well-known hallmark of cancer cells (a concept called the Warburg effect).

• Insulin Resistance

As your cells adapt to this dysfunctional fuel system, insulin resistance kicks in. Your body produces more insulin to compensate, and eventually, this overcompensation contributes to type 2 diabetes, weight gain, and metabolic syndrome.

Why This Matters More Than Ever

For decades, sugar and refined carbs have taken the heat for metabolic diseases—and rightly so. But this new research suggests that seed oils may be just as problematic—if not more.

Consider this:

• Seed oils now account for up to 80% of the average American’s fat intake
• The percentage of linoleic acid (a major PUFA) in human fat tissue has doubled since the 1950s
• The rise in seed oil consumption parallels the explosion of diabetes, obesity, and cancer
  
  

And these oils aren’t just in your frying pan—they’re in salad dressings, store-bought sauces, chips, granola bars, crackers, frozen foods, and even many so-called “health” products.

A Functional Medicine Approach: What Can You Do?

At Radiant Health & Wellness, we believe in addressing the root causes of disease—not just treating symptoms. Here’s how to protect your body and support your mitochondria:

✔️ Choose Fats That Love Your Body Back:

• Grass-fed butter or ghee
• Extra virgin olive oil
• Cold-pressed avocado oil
• Coconut oil (in moderation)
• Animal fats from pasture-raised sources (like duck fat or lard)
  

✔️ Avoid or Minimize:

• Canola oil
• Soybean oil
• Corn oil
• Safflower, sunflower, and cottonseed oil
• Anything labeled as “vegetable oil”
  

✔️ Eat More Whole, Unprocessed Foods:

• Reducing your intake of packaged and processed foods is one of the most effective ways to cut back on seed oils and reclaim your metabolic health.

Final Thoughts

Our bodies weren’t designed to run on industrial oils. When we feed them what they were never meant to process, things go wrong—slowly, silently, and systemically.

If you're struggling with fatigue, blood sugar imbalances, weight that won't budge, or a general feeling that something’s “off” despite normal labs, it’s time to look deeper. You don’t need another fad diet—you need answers rooted in science and individualized to your body’s needs.

Want to dig deeper?

Let’s uncover what’s driving your symptoms—whether it’s seed oils, sugar, stress, or something else entirely. Book a Functional Medicine consultation today at Radiant Health and Wellness.

References:

• Knobbe, C. J. (2024). The seed oil theory of chronic disease: A metabolic and mitochondrial perspective. Frontiers in Nutrition.
• DiNicolantonio JJ, et al. (2020). “Saturated fat is not the major issue.” BMJ.