Good Science, Bad Science

I just finished slogging through 460 pages detailing 150 years of research on nutrition, obesity, disease, and weight gain accompanied by 100 pages of documentation: Good Calories, Bad Calories written by Gary Taubes and just published by Alfred A. Knofp. Had I been Gary Taubes’s editor, I would have insisted on putting the conclusions up front. But, no, someone like me didn’t edit this book; so this reader had to read every study, every turn, every machination, every bungle, every fabrication, excuse, rationalization, and machination that led to the current travesty of nutrition science.

The book is brilliant and well-worth the slog. But let me give away the end for those less patient than I am. Without the work of slogging through the studies, the results will be quite shocking. So read the book. In the interim, here is the upshot:

Dietary fat doesn’t make you fat or prone to heart attacks or cancer. In fact, some studies suggest that the less fat you eat, the more likely you are to get cancer.

Carbohydrates—especially refined ones, sucrose, and high-fructose corn syrup—upset the body’s homeostatic mechanisms. They spur insulin secretion. “Insulin is the primary regulator of fat storage. When insulin levels are elevated—either chronically or after a meal—we accumulate fat in our fat tissue. When insulin levels fall, we release fat from our fat tissue and use it for fuel.” (p. 454) These carbohydrates may be the most likely causes of “the diseases of civilization,” including heart disease, cancer, Alzheimer’s (inadvertently), diabetes, and metabolic syndrome.

To say that obesity is the result of eating too much is like saying that alcoholism is the result of drinking too much. Both are tautologies, and both fail to cover cases where people eat “too much” without getting fat or drink too much without becoming alcoholics. There may well be a link between overeating and obesity (though often that link is missing), but the association tells us nothing about causation. A third factor should be considered. Taubes finds this third factor to be insulin increasing as the result of carbohydrate consumption. The more sugar or insulin floating in the blood stream, the less the body will metabolize and burn fat. (This is my way of putting it, not Taubes’s.)

“Fattening and obesity are caused by an imbalance—a disequilibrium—in the hormonal regulation of adipose tissue and fat metabolism. Fat synthesis and storage exceed the mobilization of fat from the adipose tissue and its subsequent oxidation. We become leaner when the hormonal regulation of the fat tissue reverses this balance.” (p. 454)

The notion that getting fat is a result of eating more calories than one burns off is completely unsubstantiated. Cutting back on calories makes one hungry, makes the metabolism slow down, makes the person less likely to exercise. Exercising more makes one hungry. The best way to control eating is to control hunger, and hunger is an effect of how much insulin is cruising through the system. Carbohydrates spur insulin, inhibit fat mobilization, and make us hungry. The less insulin, the less hungry one is. The more fat we eat without eating carbohydrates, the more satisfied we are.

How can what Taubes be saying be true when we’ve heard everything to the contrary? Taubes makes a compelling case that all we’ve heard has been the result of a bandwagon or (see John Tierney’s terrific article) a cascade effect: one researcher comes up with a theory that fat is linked to heart disease, a theory poorly tested; this theory gets a lot of good press; the next researcher who comes along is sobered by the new conventional wisdom and interprets his results in keeping; others select studies and cases that serve to back up the conventional view; and soon anyone who dares to say anything to the contrary is dubbed a heretic. Or dismissed without comment. This is a book that will interest the philosopher of science as much as the person worried about how to feed her kids.

Taubes’s book, Good Calories, Bad Calories, points the way forward to some good science.