Studies say Atkins diet a short-term fix
After year, advantage over other diets gone
Two new studies have found that the Atkins low-carbohydrate diet outperforms traditional low-fat diets in the short-term, but offers no weight-loss advantage over more conventional diets after one year.
The findings buttress previous experiments that found the wildly popular diet to be a short-term fix that in the long-term is no better than more conventional approaches.
The well-known nutrition plan now appears to be on the footing as numerous other commercial diets: effective for temporary trimming but unproven as a method for reducing weight-related health risks over a lifetime.
‘‘I don’t care that low-carb diets produce short-term weight loss; all diets do,’’ said a Yale nutrition specialist, Dr. David L. Katz. ‘‘When you go out a year, the weight loss benefits disappear.’’
With a majority of Americans now classified as obese and overweight, millions have turned to the theories of Dr. Robert C. Atkins, a late author whose ideas have spawned a dieting empire. He offered a tasty fix: Dieters could consume meat to their hearts’ content, but must avoid breads and other carbohydrates.
The inclusion of greasy, buttery foods appealed to millions struggling with blander diets. Atkins’s recommendations, though two decades old, hit critical mass several years ago and have since overturned the conventional food pyramid wisdom that placed carbohydrates at the base of a healthy diet. But many nutritionists fretted that heavy fat consumption would increase the risk of heart disease.
Two papers published a year ago in the New England Journal of Medicine found that those on Atkins-style diets lost twice as much weight over six months as those on a low-fat program. But then the Atkins dieters regained some of the weight and after one year were at the same weightloss level as the low-fat group.
The new papers, in today’s edition of the Annals of Internal Medicine, mirror those findings.
In the first study, funded by the nonpro fit Robert C. Atkins Foundation and conducted by Duke University researchers, 120 obese people were randomly assigned to either the Atkins plan or a lowfat diet. The foundation is separate from Atkins Nutritionals Inc., which sells the diet products, and the foundation had no role in how the research was conducted.
After six months, the Atkins group lost an average of 26 pounds, and the low-fat group lost 14 pounds on average. The Atkins group, which received intensive counseling by Atkins-trained physicians, also lost more body fat, lowered their triglycerides more, and raised their highdensity lipoprotein levels, or good cholesterol, more.
But the Atkins group reported more side effects such as constipation and headaches; however, more of them were able to adhere to their assigned diet.
‘‘I think there’s been enough consistency to now say that the low-carb diet is more effective at six months,’’ said Dr. William S. Yancy Jr.of Duke, lead author of the study. But he added, ‘‘If it’s not effective at a year, it negates what happens at six months.’’
The second study, funded by the federal government and conducted at a Philadelphia veteran’s hospital, found no statistical difference in the overall weight loss in the two groups after one year. This study, following 132 obese adults, involved the same group of patients who, a year ago in the New England Journal, were reported to have more pronounced six-month weight loss among Atkins patients. But after a year, both groups were at the same point, down from their original weights by an average of 10 to 16 pounds. And more than a third of the patients in both groups had dropped out.
The new studies confirm that Atkins dieters do not suffer spikes in cholesterol or triglycerides, as many had worried. In fact, both heart disease risk factors were reduced more than in low-fat dieters, both after six months and one year. Therefore, the Atkins diet could be considered an equal to some other traditional diets as a quick weight-loss alternative.
But what would happen after one year is unknown: There are no studies following Atkins dieters beyond that period. Many nutritionists said they suspect that much of the weight lost would be regained, as has been the case with most other commercial diets.
This is the gold standard for nutritionists: A diet than can take off and keep off weight.
‘‘The issue really is: What happens when people lose the weight they want to lose or go off the diet? We still don’t know about its long-term effectiveness,’’ said Tufts University nutritionist Alice Lichtenstein.
To lessen the risk of obesity-related ailments like diabetes and heart disease, weight loss must be long-lasting, say nutrition specialists. In this regard, no simple commercial diet plan has been found to be effective.
‘‘People have to learn how to modify their lives, less calories, more exercise,’’ Lichtenstein said. ‘‘And it has to be permanent.’’
Raja Mishra can be reached at rmishra@globe.com. 