Wednesday, December 21, 2011

High-Fat Diets Cause Insulin Resistance Despite An Increase In Muscle Mitochondria

Here's Laurie's recent post:
Scientists Know that Fatty Diets Cause Blood Sugar Problems

I have to say, I agree with her. High-fat diets likely contribute to insulin resistance, and in turn, diabetes. I've read a number of studies over the years that support this link - both epidemiological and clinical studies, the latter on animals as well as humans. I don't know why this link isn't discussed much in the media.

I've also wondered whether low-carb (and so, by default, high-fat) diets disguise this problem. As long as you continue to eat very little carbohydrate, insulin resistance that a high-fat diet may be promoting might not be apparent - that is, if you're just looking at blood glucose levels.

(The rats in the study Laurie mentions, the ones that experienced insulin resistance, were eating about 50% of their calories from fat and 30% from carbohydrate.  There were 2 high-fat groups: one eating flax seed and olive oil, the other lard and corn oil.)


Mike said...

I think the key to ask is if the insulin resistance is pathological, or non-pathological.

Ben P. DaSalt said...

Your blog was what informed me of this phenomenon in a clear and persuasive manor, back in 2008 and onwards. You never seemed to hold a strong bias either way as far as fat vs. carbohydrates. You appeared to be following the data, one of the reasons I became a regular reader.

Back then I wondered why low-carb bloggers didn’t appear to know about this, but I’m seeing it picked up a bit more as low-carbers shift towards ancestral health paradigms and are becoming skeptical of carbophobia, at least with whole food sources.

Seems like the friction is with fat and carbohydrate consumption. Low fat “works.” Low-carb “works.” For similar reasons since they shift fat to carbohydrate ratios, reducing the conflict and also tend to moderate calories. So yes, fats “are bad” and carbs “are bad” depending on which macronutrient one wants to favor over the other.

But it does seem like straying from low-carb even a little for some people can be more impactful since insulin resistance is so elevated.

Laurie Endicott Thomas said...

Yes, a low carbohydrate intake could mask insulin resistance!

Fortunately, clinical studies have shown that insulin sensitivity can be rapidly restored if people with type 2 diabetes switch to a diet based on unrefined starches and vegetables.

I suspect that insulin resistance is adaptive. It reduces the flow of fat into adipose tissue and thus helps decrease the rate at which people fatten on a fattening diet. If the type 2 diabetes gets bad enough, it even leads to weight loss. Notice that many of the people who are spectacularly fat have no trouble with their blood sugar. Notice also that the drugs that are used to increase exposure to insulin or to overcome insulin resistance have weight gain as a side effect.