Dietary Fat and Blood Sugar
 

According to the Forks Over Knives movie, (I know, it's mostly BS,) dietary fat keeps insulin from entering the muscle cells, and glucose is kept in the blood, driving it up. That might be good to keep from gaining weight but the claim the movie makes about this effect causing type 2 diabetes got me wondering. Any scientific rebuttal? Does dietary fat clog the muscle cells and create havoc with blood sugar?

The movie is mixed up about what causes type 2 diabetes. It's about insulin, not about the fat.

It goes like this:

eating the wrong diet can cause insulin overload - too high, too often
insulin overload causes insulin resistance
insulin resistance impairs the burning of glucose
Impaired glucose burning while eating the same causes excess glucose
excess glucose stays in the bloodstream and continues to rise

There's a neat science article from a while back that talks about how you can see insulin resistance years before developing type 2.

Problems in the Furnace from Howard Hughes Medical Institute

I haven't seen the movie but I seem to recall studies where they have people eat a fatty meal and then show that glucose stays high after the meal. Fat phobes think fat is the bad actor there, so one could interpret that data such that fat is the cause. Another interpretation is it was the high insulin overall from whatever the meal was, and the fat is just a bystander.

If you have a healthy metabolism, and you eat a high carb, low fat diet for a few days, your body will adapt, and you'll be more insulin sensitive due to adaptations to better utilize glucose. Go on a fast or a low carb diet for a few days, and you'll be less insulin sensitive, because your body has set itself up to spare glucose. These transient changes in insulin sensitivity are interesting enough, but type II diabetes doesn't happen suddenly, it develops over the course of years. And once it has developed--going on a high carb, low fat diet may or may not be an option. It doesn't matter to your body's cells whether the fat that's competing with glucose for uptake comes from the diet, or the body's own fat stores.

A fellow named Kempner developed a Rice Diet that he used for various diseases, one of them type II diabetes. The diet consisted of rice, fruit, and white sugar. An important caveat here is that while for lean patients the diet was unrestricted, for overweight patients (where most of his type II patients likely fell) he restricted the calories--I believe it was about a thousand calories a day. Later on in his career, it made the papers that he actually whipped some of his patients, at their request, to get them to stay on the diet.

Also, even if it works, and without the whips, so, often, does a low carb diet. A low fat vegan doctor may claim that type II's can't eat any fat, or they'll be glucose intolerant. But here's the thing--a type II diabetic who eats glucose may exhibit elevated triglycerides and other lipid abnormalities. It makes as much sense to say that dietary glucose has made them fat intolerant as it would to say that dietary fat has made them glucose intolerant. Choose your intolerance, I guess. If you can. Too many diabetics do just fine on a low carb diet for anything approaching the blanket disapproval of the forks over knives people.

Dietary fat has the least impact on insulin. Thus, the famous Atkins Fat Fast for the highly insulin resistant.

This is Dr Fung's response on the dietdoctor.com site to the question of whether dietary fat causes type 2 diabetes:



Jean

Cotonpal, that is what I was looking for. A study that debunked the movie's claim. Thank you. Thank you everyone else for some great answers too.

I haven't seen the movie but I'm a big fan of Dr. Fung. I eat a lot of butter and my blood sugar is fine, although I'm not diabetic.

Judy