2 studies add weight to fight for high-fat diet

Could it be that man really isn't meant to live on bread and fruit alone?

The number of participants was small and the differences in weight loss "statistically insignificant." Still, the first multi-center controlled trials to compare the high-fat, low-carbohydrate Atkins- style diet with a conventional low-fat, high-carb plan showed surprising short-term weight-loss advantages -- as well as improved cholesterol measures.

Publication of two studies Thursday in the prestigious New England Journal of Medicine seems certain to spice up the debate over the role of protein, fats and carbohydrates in human diet and metabolism.

Unlike earlier studies that used relatively healthy volunteers to test low-carb diets, particularly the approach espoused by the late Dr. Robert Atkins, patients in the new experiments were severely obese. The average weight of one study group was 288 pounds; many of those participants had conditions such as heart disease, diabetes, hypertension and high cholesterol.

Those on the low-carb diet lost about twice as much weight after six months as those taking the low-fat approach. For the group following the Atkins plan, the weight-loss difference lasted for a year, but averaged only about 4 pounds. That amount is not considered statistically significant, in part because almost half the 73 participants in the study had dropped out.

Beyond actual weight loss, though, the studies found that people on low-carb regimens significantly reduced triglyceride (blood fat) levels.

Patients on the Atkins diet in the first study had triglycerides decline by 17 percent after a year, vs. no significant change for those on the low-fat diet. And their HDL ("good") cholesterol levels were up 11 percent, vs. just 1.6 percent for those on the conventional diet.

Those in the second study group that simply limited carbs to 30 grams a day had a 20 percent reduction in triglycerides vs. 4 percent on a low-fat diet. And among diabetic participants, those on the low- carb diet saw their fasting blood-sugar levels decline by 9 percent, compared with about 2 percent for the low-fat group.

"Our results may be surprising to some people," said Dr. Linda Stern, a primary care doctor with the VA health system in Philadelphia and a co-author of a study that randomly assigned 132 men and women to low-fat or low-carb diets for six months.

"Especially in the realm of lifestyle modification (to treat chronic illness like diabetes), we might have to broaden our horizons on what we're recommending."

Researchers said the results demonstrate the paradox of American dieting: while most adults are taking in less fat, they're not losing weight or improving their heart health as a result.

"They're restricting their fat, but they're still overeating," said Dr. Frederick Samaha, chief of cardiology at the Philadelphia Veterans Affairs Medical Center and an assistant professor of medicine at the University of Pennsylvania, who led one team. "When they overeat carbohydrates, they remain overweight and perhaps even exacerbate development of diabetes, unfavorable lipids and heart disease."

Gary Foster is an associate professor of psychiatry at Penn who led the second study carried out there and at medical centers in St. Louis and Denver. He said that "it may be premature to widely recommend low-carbohydrate approaches, but our initial findings suggest that such diets may not have the adverse effects that were anticipated."

Skepticism of the low-carb approach is still strong, however.

"This supports what we've been saying all along," said Amy Lanou, nutrition director of the meat-averse Physicians Committee for Responsible Medicine. "High-protein, low-carbohydrate diets are extremely hard to stick with and don't work any better over the long run than a conventional 'reduce the fat' diet, which doesn't work very well either."

Drs. Robert Bonow of Northwestern University and Robert Eckel of the University of Colorado urged caution against "over- interpretation" of the studies. They warned in a commentary in the journal that even if weight loss could be sustained on the Atkins diet, the dangers of continuing to high levels of saturated fat for many years are well documented.

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