BW Online | April 8, 2003 | Count Calories, Not Carbs

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APRIL 8, 2003

NEWS ANALYSIS

Count Calories, Not Carbs
After analyzing 107 diet studies, a team of doctors says the key to losing weight is to limit the amount -- not the type -- of food you eat

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A huge meta-analysis of the wildly popular low-carbohydrate diets has proved, yet again, that there's no such thing as a free lunch. Such diets often promote the idea that pounds can be shed by avoiding bread, pasta, and other carbohydrates while eating as much fat and protein as one wants. But in a new study, a team of doctors from Stanford and Yale Universities have found that any weight loss achieved on a low-carb diet comes from consuming fewer calories, the crucial factor in a standard weight-loss diet. Carbohydrate restriction had nothing to do with it, they say.

Low-carb diets have spawned a huge industry of books, diet aids, and prepared meals in recent years. Diets such as Sugar Busters, The Zone, and most famously, the one espoused by Dr. Robert Atkins in his perennial best-seller, Dr. Atkins' Diet Revolution, have become all the rage despite skepticism expressed by much of the medical Establishment. Atkins has argued for more than 20 years that the bodies of most overeaters produce too much insulin, which converts excess carbohydrates to fat.

STICK WITH IT. By switching to a diet that's extremely low in carbohydrates, insulin production is decreased, food craving dampened, and stored fat burned off, Atkins has claimed. Adherents can eat steak, eggs, cheese, and butter but virtually no bread, pasta, fruit, or sugar -- even many vegetables are banned. Numerous medical associations, however, have warned that over time high-fat diets can lead to kidney, liver, and heart problems.

The new report published in the Apr. 9 issue of the Journal of the American Medical Assn. is the first of its kind, a review of all the scientific literature published on low-carbohydrate diets from 1996 to 2003. The researchers analyzed a total of 107 diet studies involving 3,268 people from around the world.

Although the studies differed in their carbohydrate and caloric intake, among other variables, the team was able to draw one overriding conclusion: "The greatest predictors of weight loss appear to be caloric intake and diet duration," says Dr. Dena Bravata of Stanford's Center for Primary Care & Outcomes Research.

WHAT ABOUT EXERCISE? People on diets of 60 or fewer grams of carbohydrates a day (a threshold used by many low-carb diets) did lose weight, but the loss was invariably associated with eating less and dieting longer, rather than carbohydrate intake. "The findings suggest that if you want to lose weight, you should eat fewer calories and do so over a long time period," says Bravata.

Interestingly, the researchers didn't recommend for or against low-carb diets, concluding that not enough evidence is available to make such a determination. Most of the studies in their analysis didn't last longer than 90 days, and none had participants with a mean age over 53 years old. Bravata says more studies are needed on the role of exercise in weight loss, the long-term effects of low-carb diets, and their safety for people over age 53.

By Catherine Arnst in New York
Edited by Beth Belton

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