Atkins Diet Wins Kudos in a New Study
There's no easy way to lose weight and keep the pounds off. But the Atkins diet may have an edge over other popular diets, at least at first. That's the bottom line of a new study of four diet plans that found that the high-protein, low-carbohydrate diet might slightly increase the odds of losing weight.
In the study, which appears in the current issue of the Journal of the American Medical Association, researchers at Stanford University compared four popular, brand-name diets: Atkins, which recommends a very low level of carbs (20 grams a day of carbs for the first few months, and then 50 grams after that); the Zone, favoring a 40—30—30 percent balance of carbs, protein, and fat; the LEARN program, which generally follows the USDA food pyramid and includes behavior modification tips like learning how to deal with a relapse; and the Ornish diet, which calls for no more than 10 percent of calories from fat.
The researchers studied 311 premenopausal women who were obese or overweight, averaging almost 190 pounds. Each was told to follow one of the four diets; they attended weekly diet classes for the first two months and then followed the diet books' instructions for meal planning on their own. Every few months, the researchers checked the women's weight, as well as common indicators of health such as cholesterol levels and blood pressure.
At the end of a year, the average weight loss was about 10 pounds for the Atkins group, 3- 1/2 pounds for the Zone group, almost 6 pounds for the LEARN group, and almost 5 pounds for the Ornish group. Statistically speaking, the difference was significant between Atkins and Zone—that is, it was unlikely to occur by chance alone. But even that 10-pound weight loss by the Atkins group represented only about a 5 percent decrease from the women's starting weights.
"There's no easy solution and no magic formula as far as weight loss goes,"says Alice Lichtenstein, a nutritional biochemist with the Friedman School of Nutrition Science and Policy at Tufts University.
The Atkins diet may have gotten a leg up for one simple reason: It's easier to follow, at least at first, says Christopher Gardner, lead author of the study. "Their very simple message hits it right on the head: Drastically reduce your carbs," he says. Protein may also be more filling, and the diet's emphasis on drinking lots of water may crowd out an extra sip of energy drink here or a half a cola there, resulting in weight loss.
But other studies have shown and this one suggests that, like other diets, it's harder to follow Atkins for a long time. While the Atkins group lost more weight in the first six months of the study, participants gained some back in the next six months. More follow-up is needed to determine whether the losses can be sustained.
Gardner emphasizes that Atkins is not necessarily healthy to follow over many years, either. While the Atkins group did better than the women on the other three diets on measures of HDL cholesterol and triclgycerides, over time high levels of protein may knock the body out of balance, stressing the kidneys and potentially weakening bones, he says. It's not possible to tell from the study whether it was the proportion of protein and carbs or the greater weight loss that put Atkins on top as far as cholesterol goes.
As with other comparative diet studies, the groups converged over time. The low-carb group started eating more carbs and the low-fat groups ate more fat. Because the dieters didn't actually follow the diets as directed, the results can't really be taken as an assessment of how they'd work were they followed to the letter, say Barry Sears, the doctor who invented the Zone, and Dean Ornish, the creator of his own low-fat program.
But that may be the point, says Marion Nestle, professor and former chair of the department of nutrition, food science, and public health at New York University. It's easy to plan a diet that will result in weight loss. It's much less easy to follow and maintain it. "What's sustainable is eating less and more healthfully and being more active," she says.