Metabolism

Recent articles

Leptin: a growing understanding Dec 26, 2011: In my book, I argue that leptin was used to signal "not empty" with regard to fuel supplies. It loses its signal when the tank is full and when there is glucose aplenty in the blood supply, which is why insulin screens out the leptin signal. I think this went unnoticed by readers. People seem to think that it focuses almost entirely on insulin. A nice discussion of the inceasing understanding of leptin is in the following. It completely supports the view I take in the book. Leptin's multi-system effects also fit the "expendable system" view I argue for; when you are starving, only the truly essential systems get resources. Reproduction and immunity crash. They are systems to move the genes into the future or to maintain. When there is no tommorrow, they must be sacrificed.

The Insulin Index Dec 5, 2011: The insulin index is an alternative to the glycemic index. Rather than measure the rise in blood glucose when a food is eaten as the glycemic index does, the insulin index measures the insulin response. Yet, there is some ambiguity here because the foods ingested seldom have only protein, carbohydrate, or fat. Moreover, the carbohydrate may be of several different forms such as sugar or starch (there are many starches too).

Insulin Hypersecretion and Insulin Resistance as Causes of Obesity Oct 5, 2011: Time to revisit the central role of insulin in obesity. And there is no better source than Dr. Lustig and his co-author Dr. Isganaitis in their paper, Isganaitis and Lustig. Fast food, central nervous system insulin resistance, and obesity. Arteriosclerosis (2005).

Before putting up the main paragraphs in the article, let me make a bit of an evolutionary argument for key elements of the process. They can be found in my book, The New Evolution Diet, in a compact form.

Mixing Exercise Intensities and Frequencies Aug 24, 2011: Some experts recommend one intense workout per week, others working out every day. They are too regularized and do not mix intensities and frequencies in a natural way. The Power Law gives the right mix.

Obesity and Reward Circuits Aug 22, 2011: Over eating is the conventional way of explaining obesity. I don't think much of that idea myself because it still subscribes to the energy balance model, which is nothing more than an accounting identity having nothing to do with behavior, nutrient partiioning in fat or other tissues, and hormones. The reward circuits in the brain simply do not get the signals required to indicate satiety when you eat foods, mostly carbohydrates and processed foods, that make the brain resistant to insulin and you become so fat that you become leptin resistant as well.

Dr. Barbara Corkey's Banting Lecture Aug 2, 2011: The Banting Lecture is given each year by distinguished researchers in metabolism and diabetes. This year, the lecture is given by a relative of one of our site members who thoughtfully provided the link to our Members Forum.

What a treasure this lecture is; softly spoken, but assured and full in her knowledge, Dr. Corkey sets out a new model of obesity, diabetes, and hypersinsulinemia.

How Fat and Protein Intake Alter Metabolism Jun 13, 2011: This paper reviews some of the effects on your metabolism after eating fat or protein or some combination of carbohydrate, protein and fat. The answers are not so clear, but perturbing insulin, glucagon, and C-peptide are a big part of the story.

It is the pattern of eating Apr 26, 2011: Just a tidbit from an interesting experiment. No one seems to know yet how calorie restriction (CR) extends life, if it even does in humans, though it can in mice, according to many experiments.

Now, it turns out that CR mice eat in a different pattern than do mice that eat almost all they want (the mice in this experiment were a bit restricted compared to the usual ad libitum-fed mice, so they were not quite pigging out). The CR mice ate in bursts rather than nibbling continuously. The ad libitum mice nibbled all day.

Melatonin Jan 23, 2011: Its not just about helping you sleep; its roles in metabolism and as an antioxidant are powerful.

Alternate Day Eating, Energy Balance and Metabolism Dec 6, 2010: It is pretty clear that human metabolism is adapted to the variable energy intake and expenditure that characterized the evolutionary environment, particularly through the Ice Ages. I cover aspects of this in my Why We Get Fat paper.

Nassim asked me about the concavity/convexity of energy intake and expenditure the other day on his Facebook page Nassim Taleb. You can see the discussion that ensued there. Eating every day is far different from starving one day and feasting the next, so why are they treated the same by the energy balance modelers? Because they don't know the importance of variation.