Intermittent Fasting, Fitness, & Paleolithic Nutrition

Someone shot a link to the blog about a guy who was taking Gary Taubes to task on various issues. Link to that here. Well…actually, that link is to the blog, not the specific post I wanted. Well, anyway, James’ original post had a list a greivances with Gary Taubes stuff, one of which was a statement that really left me scratching my head, that insulin was anorexic. James Kreiger said insulin reduces the sense of appetite! Now, this seemed both counter intuitive and completely against the research looking at insulin, leptin and hunger. High insulin seems to dysregulate appetite control mechanisms and it is what allows peopel to literally eat themselves to death. Mat Lalonde did soem poking around and just shot me this email:

Someone pointed you to some blog where someone was saying that insulin was a satiety hormone (made animals stop eating). This initially made no sense. I got the answer. Old school insulin research experiments involved injecting insulin into the brains of animals. They would inject one large dose of insulin and noticed that it made the animals stop eating. However, this is an acute response. Most hormones have acute and chronic responses. Acute exposure of the brain to insulin blunts hunger because it clears dopamine from the brain, which signals the end of a meal. The brain becomes insulin resistant upon chronic exposure to insulin. The chronically high levels of insulin that result interfere with the satiety hormone leptin, which makes the body think it is starving and causes the animal to eat more.

In Good Calories, Bad Calories Taubes pulls together two very interesting scenarios. One is calorie restricted in which individuals are at similar calorie intake as the Ansel Keys starvation studies, yet these individuals are NOT hungry. This is in stark contrast to the Ansel Keys folks. The difference? Taubes example was of calorie restriction plus low carb and therefore low insulin. The net result being low to no sense of hunger as compared to the literally starving Ansel Keys (calorie restricted, but high carb) group. Another interesting point by Taubes related the study of folks eating over 10,000 calories per day…folks who were sickened and distended from the amount of food they had to eat…yet were STILL HUNGRY! High insulin, even in a hyper caloric state, can bypass satiety centers in the brain.

This is nothing new. Hyperinsulinism causes some very odd things to happen. Cardiac enlargement is caused in part by elevated IGF (insulin like growth factor) due to a reduction in IGF binding protein under conditions of elevated insulin. This left ventricular enlargement can lead to congestive heart failure and interestingly, a situation of IGF RESISTANCE in the cardiac tissue which may be a precipitator to more advanced cardiac events.

Anyway, the self anointed “BS-Detective” cherry-picked this notion that insulin is anorexic, and then failed to look that the whole picture. When you look at his blog roll you see a list of characters who do not much like Taubes, paleo or anything they have not generated. BS detective? Hmmm…