Almost six months after his death, the late Dr. Robert Atkins, famous for his low-carb, higher-calorie diet, may be proven right. While alive, Atkins endured constant criticism from leading nutrition and medical experts for his promotion of the Atkins Diet, an eating regimen which allows weight watchers to actually consume more calories then regular dieters, but lose more weight.

Over the past year, several small studies have shown, to many experts’ surprise, that the Atkins approach actually does work better, at least in the short run. Dieters lose more than those on a standard American Heart Association plan without driving up their cholesterol levels, as many feared would happen.

Now the results of a smaller, more concentrated study led by Penelope Greene of the Harvard School of Public Health found that people eating an extra 300 calories a day on a very low-carb regimen lost just as much during a 12-week study as those on a standard low fat diet.

The results have shocked many in the weight-loss and nutrition industries because in effect, the results go against one of the most revered beliefs in nutrition: A calorie is a calorie is a calorie. It does not matter whether they come from bacon or mashed potatoes; they all go on the waistline in just the same way.

“There does indeed seem to be something about a low-carb diet that says you can eat more calories and lose a similar amount of weight,” Greene said in a presentation to the American Association for the Study of Obesity this week.

But critics are still not impressed.

“It doesn’t make sense, does it?” said nutrition researcher and acclaimed author Barbara Rolls. “It violates the laws of thermodynamics. No one has ever found any miraculous metabolic effects.”

According to nutritionist Stephen Byrnes, the low-carb fad is nothing new.

“Throughout history, writers such as Anthelme Savarin, William Banting, Vilhjamur Stefansson and Weston Price, in one way or another, all advocated lower carb diets,” Byrnes said. “It is only in recent years, however, that the low-carb diet has achieved such wide and sustained popularity.”

The Atkins Diet requires users to reduce their carbohydrate intake to less than 40 grams a day in order to stimulate excess insulin release by the pancreas. This flood of insulin is then supposed to prohibit the body’s natural process of breaking down glucose ? not fat ? for energy. By halting this natural process, the Atkins Diet then allows the body to break down fat for energy instead, which ultimately promotes weight loss.

The Harvard study aimed to prove the effects of a low-carb diet once and for all. In the study, 21 overweight volunteers were divided into three categories: Two groups were randomly assigned to either low fat or low-carb diets with 1,500 calories for women and 1,800 for men; a third group was also low-carb but got an extra 300 calories a day.

In the end, everyone lost weight. Those on the lower-cal, low-carb regimen took off an average of 23 pounds, while people who got the same calories on the low fat approach lost 17 pounds. The big surprise, though, was that volunteers getting the extra 300 calories a day of low-carb food lost 20 pounds.

Greene emphasizes that the study’s results are still fresh, and she admits that she can still only guess why the people getting the extra calories did so well.

“Maybe they burned up more calories digesting their food,” Greene said.