Monday, April 18, 2011

Taubes - His Golden Oldie

This article, published in 2003, was one of Taubes' first shots at the lipid hypothesis (cholesterol causes heart disease).  The topic is as controversial today as it was then, with a few exceptions, such as the USDA Dietary Guidelines indicating that, among saturated fats, stearic acid is benign.  This is as concise a summary of the issue as you'll find - note, the alternative hypothesis is also called the 'carbohydrate hypothesis':
The science behind the alternative hypothesis can be called Endocrinology 101, which is how it's referred to by David Ludwig, a researcher at Harvard Medical School who runs the pediatric obesity clinic at Children's Hospital Boston, and who prescribes his own version of a carbohydrate-restricted diet to his patients. Endocrinology 101 requires an understanding of how carbohydrates affect insulin and blood sugar and in turn fat metabolism and appetite. This is basic endocrinology, Ludwig says, which is the study of hormones, and it is still considered radical because the low-fat dietary wisdom emerged in the 1960's from researchers almost exclusively concerned with the effect of fat on cholesterol and heart disease. At the time, Endocrinology 101 was still underdeveloped, and so it was ignored. Now that this science is becoming clear, it has to fight a quarter century of anti-fat prejudice.
The alternative hypothesis also comes with an implication that is worth considering for a moment, because it's a whopper, and it may indeed be an obstacle to its acceptance. If the alternative hypothesis is right -- still a big ''if'' -- then it strongly suggests that the ongoing epidemic of obesity in America and elsewhere is not, as we are constantly told, due simply to a collective lack of will power and a failure to exercise. Rather it occurred, as Atkins has been saying (along with Barry Sears, author of ''The Zone''), because the public health authorities told us unwittingly, but with the best of intentions, to eat precisely those foods that would make us fat, and we did. We ate more fat-free carbohydrates, which, in turn, made us hungrier and then heavier. Put simply, if the alternative hypothesis is right, then a low-fat diet is not by definition a healthy diet. In practice, such a diet cannot help being high in carbohydrates, and that can lead to obesity, and perhaps even heart disease. ''For a large percentage of the population, perhaps 30 to 40 percent, low-fat diets are counterproductive,'' says Eleftheria Maratos-Flier, director of obesity research at Harvard's prestigious Joslin Diabetes Center. ''They have the paradoxical effect of making people gain weight.''
For those would be leaders in field of nutrition, "people of consequence", who unwittingly told us to eat a diet that's (possibly) killing us - how much evidence will they need put in their faces to change their minds?  Perhaps more significantly, how many of them have the gumption to truly chase the truth in the carbohydrate hypothesis?  Will they invest their time and reputations in the types of expensive studies that will measure the hypothesis accurately? It would be much more comfortable to sit back and say "it's a toxic food environment and people are fat and sick because they eat too much and exercise too little."

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