When it comes to cooking oil, there is a lot of conflicting information out there. Are all oils good? Is butter bad? What should I buy? What should I avoid?

In the early 1900s, it became clear that trans fats were bad for our health and are strongly connected with heart disease. Then, the idea that all saturated fats were bad took hold and people started consuming vegetable and seed oils in much higher quantities. The problem is that these oils are not all created equal, and although they’re unsaturated, they can still be detrimental to our health.

The way that vegetable and seed oils are made is a very complex process that uses chemicals like hexane to extract the oil from the vegetable or seed. The product of this extraction is initially a grey, murky, liquid that then has to be deodorized, winterized and bleached in an industrial plant before it’s ready to be put on store shelves. The processing of these oils strips them of many nutrients and creates a rancid product. Therefore, when these oils are heated or exposed to light, they oxidize very quickly and create dangerous, toxic chemical compounds that can lead to chronic diseases like cancer. These oils are also very high in omega-6 fatty acids which contribute significantly to inflammation and chronic disease. Some of these highly refined, pro-inflammatory oils include sunflower oil, safflower, oil, corn oil, soybean oil, palm oil, canola oil, and (especially) cottonseed oil and are found in almost all processed foods and used in restaurants.

So, what should I eat?

• Avocado oil, grass-fed ghee (clarified butter), and algae oil are great for high-temp cooking because they have a high smoke point. These oils are also less refined and don’t oxidize as easily.
• Organic extra-virgin, cold-pressed oils like olive oil, flaxseed oil, hempseed oil, and walnut oil are higher in omega-3s and are great for low-temp cooking or drizzling on salads, vegetables, etc.

What should I avoid?

• Refined oils in general. They can be hidden in things like salad dressings, commercial peanut butters, chips, cookies, microwave popcorn, etc. Check the nutrition label to spot added, refined oils.
• Trans fats, which raise “bad” cholesterol and contribute to heart disease and inflammation. These can be found on the nutrition label under total fats or in the ingredients section as “partially hydrogenated oil.” It’s also good to understand that a product that has “0 grams of trans fat” can contain up to 0.5g. Therefore, if you have multiple servings, you may be consuming more trans-fat than you think.
• Processed meat, fried foods, margarine, and Crisco should be limited as well. These foods have the type of saturated fat that contributes to cardiovascular disease.

Bottom Line

Focus on eating foods that have the fewest steps from farm to table (or, in other words, minimally processed whole foods). Include a variety of fruits, vegetables, whole grains, lean protein, and healthy fats (like your extra-virgin olive oil!) in your diet.

Written By: Sarah Riley, MS, RD, LDN

Hyman M. Why Oil is Bad for You. Dr. Hyman. https://drhyman.com/blog/2016/01/29/why-oil-is-bad-for-you/. Published March 7, 2016. Accessed November 11, 2019