Vegetable Oils Cause Insulin Resistance

In some recent articles, we’ve seen that vegetable oils cause obesity, heart disease, promote male infertility and aging, and are just generally bad news. In this article we’ll look at the evidence that vegetable oils cause insulin resistance.

Corn oil causes insulin resistance in mice

In a study (full paper), mice were placed on a high-fat diet, with fat at 40% of calories, which is not terribly high for humans but is for mice. One group got their fat as corn oil, the other as olive oil.
The group on corn oil developed hyperinsulinemia (high blood insulin) and insulin resistance. See charts below.

The corn oil diet also spontaneously decreased locomotor activity, and by a great deal. See charts below.

Could increasing consumption of seed oils like corn oil be partly responsible for an increase in couch potato lifestyle? Maybe people who consume a lot of this stuff don’t feel like moving around much, and therefore increased seed oil consumption contributes to obesity by decreasing the amount of exercise.
Excess omega-6 consumption in mice is associated with negative metabolic and cardiovascular outcomes. Seed oils are loaded with omega-6 fatty acids.

Decreasing seed oil consumption in humans

That’s all very well for mice, but what about in humans? Does decreasing consumption of seed oils do anything for metabolism or obesity?
Turns out, it does.
A group of 93 men with non-alcoholic fatty liver disease, which is a consequence of obesity as well as sugar and seed oil consumption, were randomized to use either olive oil, canola oil, or soybean oil for cooking, at no more than 20 g a day. The study took place in India, where there’s a high consumption of seed oils in cooking – just like there is here in the U.S.
The olive oil group lost weight, and compared to canola oil, decreased insulin resistance and fasting blood sugar, and increased HDL. The canola oil group improved in some measures, but not as much as the olive oil group. (Canola is a “less bad” seed oil.) No changes were seen in the soybean oil group.
This study shows that a relatively small dietary change, using olive oil instead of soybean oil for cooking, can result in significant improvments in metabolism, and lends more evidence to the concept that seed (vegetable) oils cause obesity.

The health establishment recommends seed oils

The American Heart Association recommends “heart-healthy” seed oils. Here’s their list of “healthy” oils:

  • Canola
  • Corn
  • Olive
  • Peanut
  • Safflower
  • Soybean
  • Sunflower

The only one on that list that’s truly healthy is olive oil. The others will make you fat, diabetic, and give you heart disease.
Other establishment health organizations make the same claims.
Their advice is perverse. You’re much better off doing the opposite.
Their counsels have also fueled the obesity epidemic.
The evidence they’ve used for their recommendations is wrong. Re-analysis of studies that randomized people to polyunsaturated fats as are found in seed oils found that benefits occurred only when omega-3 fatty acids were more or less accidentally increased. When omega-6 alone was increased, death rates increased.
The evidence they’ve used is hopelessly biased.
Vegetable oils are better termed industrial seed oils both for their source, which is not vegetables but seeds, and for their mode of production, an industrial process that uses high heat and organic, gasoline-like solvents.
If you want to preserve or attain good health, don’t use them.
If you need fat for cooking, use butter, ghee, lard, tallow, or coconut oil. For cold uses, olive oil.

PS: For more on how to live longer, see my book Stop the Clock.

PPS: Check out my Supplements Buying Guide for Men.

 

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9 comments
Dave says October 1, 2017

Mr. Mangan, what are your thoughts on avocado oil? Avocado oil and avocado mayonnaise are now available, and the oil is marketed as having a high “smoke point” which, as I understand it, is supposed to be good for cooking at high heat.

Reply
    P. D. Mangan says October 1, 2017

    Avocado oil is fine, very similar to olive oil.

    Reply
Drifter says October 2, 2017

Just for the record in case any of the assembled braintrust here ever gets into a discussion with someone under the influence of mainstream health thinking, there has been a study being cited to defend seed oils which compared seed oils to saturated fat for their affect on insulin resistance and the seeds oils appeared to be the slight winner. The problem as far as I know however, is that it was a very short-term study (7-10 days I think), and as Ron Rosedale in particular has stressed, dietary saturated fat can in fact impair insulin sensitivity until one is adapted to it, which for a sugar-burner adapting to fat intake, takes somewhere between 2-6 weeks. This is why he recommends that people switching form a high-carb to a high-fat diet go easy on the saturated fat for the first 6 weeks or so.
Also, some people cite short -term FMD studies to suggest that olive oil is a problem, however again, this has been shown (e.g. by Volek) to not be an issue after a period of adaptation.

Reply
    P. D. Mangan says October 2, 2017

    Thanks, Drifter. “Assembled braintrust” – I love it. I’m not aware of either of the studies you mention, so if you come across them, that would be good to know.

    Reply
Nikita says October 3, 2017

Is sesame oil and/or mustard oil considered vegetable oil?

Reply
    P. D. Mangan says October 3, 2017

    Sesame oil, yes (seed oil). I don’t know anything about mustard oil.

    Reply
      oil boy says October 7, 2017

      so, we should definitely put peanut oil in the “bad” seed oil categories?

      Reply
        P. D. Mangan says October 8, 2017

        Yes. It may be less bad than some, but there are better alternatives.

        Reply
Rob says October 15, 2017

All you need to know about the industrial seed oils is how they are made (there are videos online that show the process). Basically, it involves a harsh extraction process that includes bleaching, deodorizing and the use of the highly toxic solvent hexane. Does that sound like something humans were meant to consume? No thanks…………

Reply
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