TUESDAY, March 6, 2007 (HealthDay News) -- The low-carbohydrate, high-protein Atkins diet has nabbed first place in a yearlong, U.S. government-funded study of four popular weight-loss regimens.
Women on the Atkins plan lost nearly 11 pounds on average over 12 months -- almost double that of participants on the Zone diet, the Ornish diet, and a diet favored by nutritionists called LEARN.
There didn't seem to be a downside to the Atkins diet, either -- at least in the short-term. The Stanford University researchers who conducted the trial of 311 overweight women found no differences in heart disease risk factors between the four groups, despite the fact that Atkins practitioners were given free rein when it came to fat intake.
"We've all been worried that the high saturated fat content of Atkins would be bad for you," said study author Christopher Gardner, an assistant professor of medicine at Stanford. The plan's high-fat levels "still make us nervous," he said, "but I think the weight loss that comes with the diet must be more powerful" in keeping cholesterol and other heart risk factors at bay.
The study, published in the March 7 issue of the Journal of the American Medical Association, is perhaps the most independent and rigorously conducted comparison of popular diets yet attempted. Even so, it had its critics.
"Yes, on the Atkins diet, the women may have lost a little bit more weight, but I'm not so sure about their quality of life -- that's the kind of information that just isn't in here," said dietitian Bonnie Taub-Dix, a New York City weight-control specialist and spokeswoman for the American Dietetic Association. "I can tell you that I have many patients that come to me that have already been on this diet, and it does not spell success if they are still coming to see me."
Since the late Dr. Robert Atkins launched his famous diet in the 1960s, debate has swirled around both its safety and effectiveness. More recently, a number of short-term studies have shown that the plan -- which advocates cutting out most breads, pastas, sugars and other carb-laden foods -- can help people shed pounds quickly.
Other bestselling diet books have offered alternative routes to leaner physiques. The hugely popular Zone diet advocates a daily rationing of food energy: 40 percent from carbohydrates, 30 percent from protein and 30 percent from fat.
Cardiologist and lifestyle guru Dr. Dean Ornish has developed his own plan. The popular Ornish diet urges users to drastically cut their fat intake to below 10 percent of daily calories.
Rounding out the four studies included in the new trial is a lesser-known regimen, the Lifestyle, Exercise, Attitudes, Relationships and Nutrition (LEARN) diet -- a more moderate diet modeled on the Food Pyramid. LEARN, which is favored by many nutritionists, allows participants to indulge in foods from all groups but emphasizes portion control, regular exercise and changes in eating behaviors.
In their study, the Stanford group randomized the 311 healthy but overweight premenopausal women to one of the four diet plans.
Because high dropout rates have plagued previous comparison trials, nutritionists were on hand to encourage ongoing participation. Women were even given a modest stipend to help keep them on their respective diets over the 12 months of the study.
"The basis of this study was our total frustration that popular diet books are out there saying the exact opposite things and all swearing they are they way to go," Gardner said. To test each regimen's effectiveness, his group had the women follow their particular diet's instructions to the letter.
In one sense, all of the diets won, since "all of the women did succeed in losing weight on average," Gardner said. "They all got a little better blood pressure and cholesterol," too.
Women on Atkins experienced much better weight loss, however. Gardner said he only has theories as to why. One reason might be the simplicity and timeliness of the plan's central message, he said.
"If you look at the last couple decades in American dietary changes, calories have been creeping up due to refined carbohydrates -- sodas, high-fructose corn syrups, snack foods," he said. "I think that Atkins may have been right on the money in terms of the thing that's been causing us to gain weight."
Replacing carbs with fat and protein may have helped, too. "Remember, you can eat a lot of rice or pasta before you actually feel full," said dietitian Tara Miller, program director of New York University's Center for Corporate Wellness. "With a high-fat diet, you are going to fill up faster."
Still, a one-year trial, however well-conducted, is simply not long enough to gauge the long-term safety of any "extreme" diet, the experts said.
Because blood glucose reacts particularly strongly to excessive carbohydrate intake, lowering carbs "might assist blood sugar control," said Harvard endocrinologist Dr. Barbara Kahn. "But the [potentially] harmful part has to do whether all those fats over the years are going to lead to more cardiovascular disease. That's the next thing that needs to be studied."
Whether most people can even stick to the Atkins, Zone or other plan for a year or more may be the real question, Miller said. "None of these diets are things that you can maintain day to day without a lot of forethought," she said. "If it does not fit your lifestyle, no matter how great a diet it is, it is not going to benefit you, because you aren't going to be able to maintain it."
That's a lesson Richard Boucher, a 42-year-old construction equipment salesman from Placentia, Calif., learned the hard way. Boucher -- who has been battling his weight since his early 30s -- first turned to the Ornish, Zone and South Beach diets for help. He'd drop some weight, but the diets' tough restrictions beat him every time, he said.
Since then, Boucher has brought his weight under control, slimming down from a top weight of 270 pounds to the 200 pounds he maintains today.
But first, he had to throw out all his diet books.
"I found that a common-sense approach works best for me," Boucher said. "A lot of portion control -- when I'm full, I just walk away. I stay away from lots of pasta and sugars. I exercise regularly. In the end, you have to do what makes sense and works for you."
Find out more about healthy weight control at the American Dietetic Association.