Multitudes swear by the high-fat, low-carbohydrate Atkins diet, and now a series of studies, albeit small ones, are making even the most ardent critics take another look at the diet's benefits.
For years, the Atkins formula of sparing carbohydrates and loading up on taboo fatty foods has been blasphemy to many in the health establishment, who view it as a formula for cardiovascular ruin.
The number of overweight people who took part in the recent studies is small, and the research did not examine long-term ills or advantages, including how long people keep the pounds off. But the results appear to show that rather than making cholesterol soar, as many experts feared, the diet might improve it, and that volunteers take off more weight.
Researchers say much more research is necessary before the Atkins diet can be given an across-the-board endorsement, but at least they believe it is safe enough to take into much larger studies.
At least three formal studies of the Atkins diet have been presented at medical conferences during the past year, and the results have been similar. The latest, conducted by Dr. Eric Westman of Duke University, was presented Monday at the annual scientific meeting of the American Heart Association, long a stronghold of support for the traditional low-fat approach.
Westman, an internist at Duke's diet and fitness center, said he studied the Atkins approach because of concern over so many patients and friends taking it up. The research was financed by the Dr. Robert C. Atkins Foundation in New York City, which was founded by the doctor who developed the diet.
Westman studied 120 overweight volunteers, who were randomly assigned to the Atkins diet or the heart association's Step 1 diet, a widely used low-fat approach. On the Atkins diet, people limited their carbs to less than 20 grams a day, and 60 percent of their calories came from fat.
"It was high fat, off the scale," he said.
After six months, the people on the Atkins diet had lost an average of 31 pounds, compared with 20 pounds on the AHA diet, and more people stuck with the Atkins regimen.
Cholesterol fell slightly in both groups. However, those on the Atkins diet had an 11 percent increase in HDL, the good cholesterol, and a 49 percent drop in triglycerides. On the AHA diet, HDL was unchanged, and triglycerides dropped 22 percent. High triglycerides might raise the risk of heart disease.
While the volunteers' amounts of LDL, the bad cholesterol, did not change much on either diet, there was evidence that it had shifted to a form that might be less likely to clog the arteries.
"More study is necessary before such a diet can be recommended," Westman said. "However, a concern about serum lipid (cholesterol) elevations should not impede such research."
No single study is likely to change minds on the issue, especially since an initial weight loss is hard to maintain on any diet. Some answers could come from a yearlong study being sponsored by the National Institutes of Health. That experiment, being directed by Dr. Gary Foster of the University of Pennsylvania, will test the Atkins diet on 360 patients.
In the meantime, the heart association's president, Dr. Robert Bonow of Northwestern University, said the organization will reconsider the Atkins diet as more data is available.
Dr. Alice Lichtenstein, a nutrition expert at Tufts University, said she thinks too much is made of the amounts of carbohydrates and fats in people's diets as they try to shed weight.
"There is no magic combination of fat versus carbs versus protein," she said. "It doesn't matter in the long run. The bottom line is calories, calories, calories."