A month after Dr. Robert C. Atkins' death, his much-ridiculed diet has received its most powerful scientific support yet: two studies in one of medicine's most distinguished journals show it really does help people lose weight faster without raising their cholesterol.

The research, reported in the New England Journal of Medicine, found that people on the high-protein, high-fat, low-carbohydrate Atkins diet lose twice as much weight over six months as those on the standard low-fat diet recommended by most major health organizations.

However, one of the studies found that the Atkins dieters regain much of the weight by the end of one year.

Atkins, who died April 17 at age 72 after falling and hitting his head on an icy sidewalk, lived to see several shorter studies that found, to researchers' great surprise, that his diet is effective and healthy in the short run.

Although those reports have been presented at medical conferences, none until now has been published in a top-tier journal. And one of the studies in the journal lasted a year, making it the longest one yet.

"For the last 20 years that I've been helping people lose weight, I've been trashing the Atkins diet -- without any real data to rely on," said Dr. Michael Hamilton, an obesity researcher who was not part of either study. "Now we have some data to give us some guidance."

Now, he said, he would neither trash it nor endorse it. "I'm going to say I don't know. The evidence isn't in," he said.

One study ran six months and was conducted by the U.S. Veterans Affairs Department; the year-long study was led by Gary D. Foster, who runs the weight-loss program at the University of Pennsylvania School of Medicine.

Atkins's diet books have sold 15 million copies since the first one was published in 1972. From the start, doctors branded the Atkins diet foolish and dangerous, warning that the large amounts of beef and fat would lead to sky-high cholesterol levels.

In both studies, the Atkins dieters generally had better levels of "good" cholesterol and triglycerides, or fats in the blood. There was no difference in "bad" cholesterol or blood pressure.

Dr. Frederick F. Samaha of the Philadelphia Veterans Affairs Medical Center, who led the VA study, said both studies indicate people do lose more weight on Atkins, "but the difference is not great."

The important finding, Foster said, is that the Atkins diet appears to be a healthy short-term way to lose weight. Nobody has studied it long enough to tell whether it is a healthy way to maintain that loss.