If you go on a low-carbohydrate diet to shed weight, you've probably made a good decision, according to a new report by Stanford University researchers.
Just don't expect miracles.
In the largest head-to-head study of competing diets so far, low-carb plans such as the Atkins Diet turned out to be safe and effective for losing weight and improving cardiovascular health - at least in the short run.
In fact, women who aggressively restricted carbs lost nearly twice as much weight over six months as women on higher-carb diets, the Journal of the American Medical Association reported today.
After a year, the low-carb dieters also saw greater improvement in cardiovascular disease risk factors - such as blood pressure and cholesterol.
The bad news: Even those on the Atkins plan, which outscored three competing diets, were down only 10 pounds after a year. And on every plan, by the end of the study, most dieters were slowly but surely regaining the weight they had lost.
"It shows that people will steadily go back to their old habits," said Dr. Lawrence J. Cheskin, director of the Johns Hopkins Weight Management Center. "After two years, you might find that everybody has regained everything."
Still, researchers welcomed the news that popular low-carb diets are safe and effective - if not a panacea for obesity.
"There is increasingly some evidence that in the short term you might be able to lose more weight on a low-carbohydrate, high-protein diet," Cheskin said.
Christopher D. Gardner, a professor of medicine at Stanford and the lead author on the study, also cautioned that the long-term safety of low-carb, high-protein diets is still in question.
"We don't know what a high-protein diet would do over 10 years," he said. "It could impair kidney function or leach calcium out of the bones. But we didn't look at that."
The study is the largest yet to explore the difference between popular diets and was intended to scientifically address concerns about low-carbohydrate plans. "We haven't had a lot of data on these diets," Gardner said.
The researchers studied four diets representing a range of recommended carbohydrate consumption.
Three of the diets - Atkins, Zone and Ornish - were created by individual doctors and popularized in books. The fourth was based on federal dietary guidelines and dubbed LEARN, for Lifestyle, Exercise, Attitudes, Relationships and Nutrition.
