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Sunday, May 25, 2003In the study, 132 men and women were randomly put on either a low-fat or low-carbohydrate diet for six months. The low-carbohydrate group was told to limit carbohydrate intake to 30 grams per day. They received counseling on healthy types of fat, such as omega-3 fatty acids, but had no limit on total fat intake. The low-fat group was put on a calorie-restricted diet, with no more than 30 percent of total caloric intake from fat. Overall, volunteers assigned to a low-carbohydrate diet lost an average of about 13 pounds, compared to 4 pounds for the low-fat group. The low-carbohydrate dieters reduced their levels of triglycerides--blood fats that, like cholesterol, may contribute to clogged arteries--by an average of 20 percent, versus 4 percent for the low-fat group. There were no significant changes in cholesterol or blood pressure levels in either group. Sounds like low-carbohydrate diets are the answer. But wait, there’s something missing from the media report. In the study, the two groups consumed different amounts of calories. At the beginning of the study the people in the low-fat diet group were consuming an average of 1848 calories a day (Give or take 1338 calories. Talk about a spread!). At the end of the study, the low-fat group were eating 1,576 calories a day (give or take 760 calories). During the course of the study they were eating on average 272 fewer calories a day than they usually consumed. The low-carbohydrate group began with a base-line daily calorie intake of 2090 calories (give or take 1055 calories.) By the end of the study they were eating an average of 1630 calories a day (give or take 894 calories), or 460 fewer calories a day than they normally ate. Of course they lost more weight. They had a greater calorie deficit from baseline than the low-fat diet group. There may be some truth to high-carbohydrate diets contributing to insulin resistance, but there’s no escaping the fact that when it comes to weight loss, it’s still calories that count the most. To the authors' credit they admit that the problem is not necessarily what you eat, but how much you eat: The authors said the study results underscore the paradox of America's fascination with low-fat eating: Americans are taking in less fat, but not losing weight or improving their cardiovascular health as a result. "People have gotten the message loud and clear--they're restricting their fat," said Samaha. "But they're still overeating. And when they overeat carbohydrates, they remain overweight and perhaps even exacerbate the development and management of diabetes, unfavorable lipids and heart disease. But at least they recognize that there are other factors involved in weight loss: Stern pointed out that even the best diet must be combined with other lifestyle changes, such as increased physical activity, to combat obesity. "Half the equation is to get people to be aware of what they're eating, and to eat less," she said. "The other half is to get them to move. Any weight loss program, at the VA or elsewhere, must include a formal exercise program." The other study also showed more weight loss in low-carbohydrate dieters, but it didn't include baseline calorie intake in the data. What it did show, was equally high rates of recidivism in both groups, suggesting what we all know - diets are hard to stick to forever. What it takes to maintain weight loss is a fundamental change in behavior - as fundamental as any change made by an alcoholic or a smoker when they quit their vices - and a commitment to that change forever. (Also see DB’s MedRants here and here.) posted by Sydney on 5/25/2003 07:16:00 PM 0 comments 0 Comments: |
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