Interesting editorial from the New York Times. I know it’s true for me personally when I want to lean out quickly cutting carbs usually does the trick, but mentally I struggle on a low carb diet. I think the problem we see in this industry is we see the extremes.
A CALORIE is a calorie. This truism has been the foundation of nutritional wisdom and our beliefs about obesity since the 1960s.
What it means is that a calorie of protein will generate the same energy when metabolized in a living organism as a calorie of fat or carbohydrate. When talking about obesity or why we get fat, evoking the phrase “a calorie is a calorie” is almost invariably used to imply that what we eat is relatively unimportant. We get fat because we take in more calories than we expend; we get lean if we do the opposite. Anyone who tells you otherwise, by this logic, is trying to sell you something.
But not everyone buys this calorie argument, and the dispute erupted in full force again last week. The Journal of the American Medical Association published the results of a clinical trial by Dr. David Ludwig of Boston Children’s Hospital and his collaborators. While the media tended to treat the study as another diet trial — what should we eat to maintain weight loss? — it spoke to a far more fundamental issue: What actually causes obesity? Why do we get fat in the first place? Too many calories? Or something else?
The calorie-is-a-calorie notion dates to 1878, when the great German nutritionist Max Rubner established what he called the isodynamic law.
It was applied to obesity in the early 1900s by another German — Carl Von Noorden, who was of two minds on the subject. One of his theories suggested that common obesity was all about calories in minus calories out; another, that it was about how the body partitions those calories, either for energy or into storage.
This has been the core of the controversy ever since, and it’s never gone away. If obesity is a fuel-partitioning problem — a fat-storage defect — then the trigger becomes not the quantity of food available but the quality. Now carbohydrates in the diet become the prime suspects, especially refined and easily digestible carbohydrates (foods that have what’s called a high glycemic index) and sugars.
UNTIL the 1960s, carbohydrates were indeed considered a likely suspect in obesity: “Every woman knows that carbohydrate is fattening,” as two British dietitians began a 1963 British Journal of Nutrition article.
The obvious mechanism: carbohydrates stimulate secretion of the hormone insulin, which works, among other things, to store fat in our fat cells. At the time, though, the conventional wisdom was beginning its shift: obesity was becoming an energy issue.
Carbohydrates, with less than half the calories per gram as fat, were beginning their official transformation into heart-healthy diet foods. One reason we’ve been told since to eat low-fat, carbohydrate-rich diets is this expectation that they’ll keep us thin.
via NY Times