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Atkins Diet Works; Safety Unknown

Low-Carb Dieters Lose Weight, but for How Long?

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July 18, 2002 -- After three decades of ridicule, the much-maligned Atkins diet is finally getting a little respect within medical circles. A newly published study by Duke University researchers show that the high-fat, low-carbohydrate approach to weight loss does work.

Study participants lost an average of 20 pounds during six months on the Atkins diet, but they were not followed to see if they kept the weight off. Most patients also had improved cholesterol levels at the end of the study, even though the eating plan permits unlimited quantities of fat and cholesterol-rich foods such as eggs and meat.

The study, published in the July issue of the American Journal of Medicine, was funded by a grant from diet guru Robert Atkins' Center for Complementary Medicine. Duke researcher Eric Westman, MD, says he became interested in studying the Atkins diet after several of his patients lost large amounts of weight on it.

"They were on the diet against my advice," he tells WebMD. "But it worked for them, so I became curious about it."

The study included 51 overweight or obese volunteers who were otherwise healthy and were on no prescription medications. All were placed on a very low carbohydrate diet (less than 25 grams per day), but neither calories nor portions were restricted. Dieters also took nutritional supplements a day and received exercise recommendations. After 40% of the weight-loss goal was reached, the daily amount of carbohydrates was increased to 50 grams.

Westman says a typical daily menu might include bacon and eggs for breakfast, a chef's salad for lunch, and steak or hamburger for dinner with one or two cupfuls of low-carbohydrate vegetables. The diet bans high carbohydrate foods such as bread, cereal, rice, pasta, and potatoes.

At the end of six months, 80% of the participants were still on the diet, and they had lost an average of 10% of their original body weight. LDL, or bad cholesterol, decreased in all but one of the dieters, while HDL, or good cholesterol, improved.

Westman says there is no mystery to why participants lost weight on the low-carbohydrate diet. Even though calories were not restricted, the dieters ate an average of 1,450 calories per day. Without carbohydrates the body goes into a state called ketosis, which tends to lower appetite.

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But though researchers were impressed by the weight loss, they say more study is needed to pronounce the carbohydrate-restricting diet safe.

"If this diet were a new drug, it would not meet the criteria for safety yet," Westman says. "We know that it works, we just don't know that it is safe. So it is important for people with medical conditions and for those taking prescription drugs to get medical supervision before going on this or any low-carbohydrate diet."

Harvard University weight loss expert George L. Blackburn, MD, PhD, is a critic of the Atkins diet but praised the Duke researchers who conducted this study.

"I would agree with their cautions about safety," he tells WebMD. "And I think everybody agrees that the only weight loss that is of any value is that which you can keep off. There is still no evidence that people lose weight and keep it off with these low-carbohydrate diets. Researchers have looked, but they can't find it."

Blackburn rejects the idea that a single type of food, be it fats or carbohydrates, is the villain that makes people gain weight. And he says the one thing the experts have learned in recent years is that a one-size-fits-all approach to weight loss and nutrition does not work.

"A healthy diet is one that is portion controlled and does not contain an excess of calories," he says. "And a prudent diet includes all food groups."

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