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Avoid This Harmful Oil Like Your Health Depends on It

Don Colbert, MD February 18, 2019

Written by Don Colbert, MD, board-certified in family practice and in anti-aging and integrative medicine for more than 25 years
Last reviewed and updated: October 17, 2026

Did you know you’re surrounded by one of the most harmful oils in the modern diet?

It’s in your fridge, pantry, and all over your grocery store.

While small amounts are actually necessary for health, large amounts cause a cascade of biochemical events that result in harm to your body.

What is it?

It’s soybean oil. It is the most widely used cooking oil in the United States, and it shows up in salad dressings, mayonnaise, chips, crackers, baked goods, and most restaurant fryers. For decades much of it was partially hydrogenated, which created artificial trans fats. The FDA has since removed partially hydrogenated oils from the food supply, but the bigger problem remains: we simply eat far too much of it.

Bad news.

Eaten in the large amounts found in processed and fried foods, soybean oil can push your body toward chronic inflammation, which negatively affects your heart, brain, and entire body. And, it’s not the only harmful oil for which to watch.

Avoid soybean oil at all costs. Make Keto Zone Ginger Dressing instead.

Delicious Keto Zone Ginger Dressing

Ingredients:

3 cloves garlic, minced
2 tablespoons minced fresh ginger root (remember, the skin comes off easily with the side of a spoon)
3/4 cup extra virgin olive oil
1/3 cup rice vinegar
6 Tbsp liquid aminos or lite soy sauce
2 Tbsp water
2-3 tablespoons erythritol

Instructions:

Mix all ingredients together.
Enjoy over a fresh salad, or as a seasoning oil for stir-fries.

Nutrition Info (per 1 Tbsp): 52 calories, 6 gm fat, 0 gm net carbs, 0 gm protein

Why Omega-6 Risk Now?

Why are concentrated omega-6 oils and soybean oil a rising concern?

Two words: Processed foods.

Processed foods generally contain the cheapest ingredients possible in order to keep profit margins as high as possible. Cheap soybean oil is associated with declines in:

Metabolic Health. In a 2015 mouse study, a diet high in soybean oil caused more weight gain, insulin resistance, and fatty liver than a diet high in coconut oil or even fructose (1).
Cardiovascular Health: Soybean oil has been shown to cause harmful abnormalities to cholesterol and triglycerides (2).
Heart disease: When researchers recovered data from the Sydney Diet Heart Study, men with heart disease who replaced saturated fat with safflower oil, which is rich in omega-6 linoleic acid, had higher death rates than men who did not (Ramsden, BMJ 2013).
Overall health and inflammation: Many studies have concluded that concentrated sources of omega-6 fats increase inflammation in the body (3).

How can you avoid this dangerous cheap ingredient at all costs?

Be diligent. Here’s how.

5 Steps to Reducing Harmful Oils and Concentrated Omega-6s in Your Diet

Make as much of your food as you can at home. This is simple and important, but not easy. We all have busy schedules and homemade foods take time. But, you will know what ingredients go into your foods, and you can easily avoid the harmful ones.
When you do buy commercial foods and condiments, look at every ingredient. Be on the lookout especially for soybean oil, any hydrogenated oils, and the concentrated omega-6 oils listed below.
Avoid fast food as much as possible. Or, ask what oils are used. Fast food restaurants are also more interested in their bottom line than your health. Avoid foods that are fried or made with soybean oil specifically.
When cooking, be careful what oils and fat you use. Here’s a quick list of what to use and avoid, with grams of omega-6s listed per 1 Tablespoon oil:

Use:

Organic coconut oil (0.4 gm Omega-6)
Olive Oil (1.3)
Avocado oil (1.8)
Occasional Use: high-oleic sunflower (0.5), high-oleic safflower oils (2.0)

Avoid:

Safflower oil (10.1 gm Omega-6)
Grapeseed oil (9.5)
Vegetable Oil (7.9)
Wheat Germ Oil (7.5)
Corn Oil (7.3)
Walnut Oil (7.3)
Cottonseed Oil (7.0)
Soybean (7.0)
Sunflower Oil (5.4)
Canola Oil (3.0)

5. When taking omega supplements, use supplements that contain only omega-3s, NOT omega-3 and omega-6 complexes. These complexes were first designed to deliver a healthy omega-6 to omega-3 ratio, but did not consider that most modern diets are already overloaded with omega-6 fat! There’s no need to add more.

Watch: Seed Oils and Inflammation, the Hidden Danger in Your Kitchen

In this episode, I break down the 8 seed oils I avoid and the healthy ones I use instead, how these oils are manufactured, why reused fryer oil is so inflammatory, and how the omega-6 to omega-3 ratio got so far out of balance.

What Omega-6 to Omega-3 Ratio?

Researchers believe humans evolved eating roughly equal amounts of omega-6 and omega-3 fats, a ratio close to 1:1. That is almost impossible in modern times, but a ratio of 4:1 or lower is a good goal (4).

Unfortunately, the typical Western diet now runs about 16:1 or higher!

Can You Simply Add More Omega-3s?

Adding more omega-3 foods and supplements will certainly help your health and ratio. But, only to a certain extent unless you also work to decrease omega-6 intake.

What About Natural Foods with Omega-6s?

What about the whole foods from which these harmful oils are derived? Like nuts.

While all nuts contain omega-6s and should be consumed in moderation, they do not contribute to the omega-6s nearly as significantly as their oils. Whole nuts’ fiber, protein, and other whole food nutrients slow the digestion and metabolism of the fats. They have redeeming healthful qualities.

Soybean oil does not.

Bottom Line

Be diligent in removing soybean oil from your diet, as well as other highly concentrated omega-6 harmful oils. Make as much food as possible at home using healthy oils, look at all ingredients in processed foods, avoid fast food, and supplement with a high-quality omega-3-only supplement.

The healthiest oil you can use is olive oil and the best olive oil available is grown in Greece. This is because Greek olive oil is high in antioxidant polyphenols, which scavenge free-radicals and prevent oxidation of the delicate monounsaturated fatty acids found in olive oil. You want to always look for 100% organic cold-pressed extra virgin olive oil for maximum freshness.

Get your own bottle of 100% organic high polyphenol Keto Zone Harvest Extra Virgin Olive Oil here.

Frequently Asked Questions

Which cooking oils should I avoid?

The oils highest in omega-6 linoleic acid include safflower, grapeseed, corn, cottonseed, soybean, and regular sunflower oil. They are usually highly refined and are the main fats in processed snacks, dressings, and restaurant fryers. I recommend extra virgin olive oil, avocado oil, and coconut oil instead.

Is soybean oil worse than canola oil?

Canola oil has less than half the omega-6 of soybean oil per tablespoon and contains some plant omega-3, so it is the lesser of the two. However, most canola oil is still highly refined. For everyday cooking and dressings, extra virgin olive oil and avocado oil are better choices.

Does soybean oil still contain trans fat?

Far less than it used to. The FDA determined that partially hydrogenated oils, the main source of artificial trans fat, are no longer generally recognized as safe, and they have been removed from the U.S. food supply. Small amounts of trans fat can still form when oils are refined or reused for deep frying, which is one more reason to limit fried restaurant food.

What is a healthy omega-6 to omega-3 ratio?

Researchers believe humans evolved on a ratio close to 1:1, while the typical Western diet now runs about 16:1 or higher. A ratio of 4:1 or lower is a realistic goal. You get there by cutting back on seed oils and processed foods and eating more fatty fish, or taking an omega-3 supplement.

Are whole soy foods as harmful as soybean oil?

No. Whole and fermented soy foods such as edamame, tempeh, and miso contain protein, fiber, and other nutrients, and they are a very different food from refined soybean oil. The concern in this article is the concentrated oil that shows up in so many processed and fried foods.

References

This article is for educational purposes only and is not medical advice. Talk with your own doctor before changing your diet, starting a supplement, or changing any medication. These statements have not been evaluated by the Food and Drug Administration. Products mentioned are not intended to diagnose, treat, cure, or prevent any disease.

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Don Colbert, MD

Don Colbert, MD, has been board-certified in family practice and in anti-aging and integrative medicine for more than 25 years. He is the medical director of the Divine Health Wellness Center, where he has treated more than 50,000 patients, and a New York Times bestselling author of books including The Seven Pillars of Health, What Would Jesus Eat?, Deadly Emotions and Keto Zone Diet, with more than ten million books sold. He hosts Dr. Colbert's Broadcast with his wife Mary and son Kyle, where faith meets functional medicine. He and Mary live in Orlando, Florida and Dallas, Texas.

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Avoid This Harmful Oil Like Your Health Depends on It