And then there's the recent popularity of the low-carbohydrate diet approaches. And then we also have diets that might be very low in fat, a typical Pritikin or Dean Ornish kind of diet, that have extreme restrictions on dietary fat intake.
ANNOUNCER: Many claims have been made recently that the low-carbohydrate diets can outperform traditional low fat diets.
BETH TAYLOR: So the high-protein diets that are popular right now, high-protein with either low-carb or moderate-carb. Some know them as the Atkins diet, that type of thing, or South Beach diet. One of the reasons those are probably popular is, by increasing your protein, for a lot of people, that helps with satiety or a sense of fullness, so that you're not as hungry all day long.
ANNOUNCER: What does the research show? It depends on the timeframe of the study.
SAMUEL KLEIN, MD: There have been recent, well-done research studies that have demonstrated that the Atkins diet generates greater weight loss at six months than a more conventional, traditional low-fat dietary approach.
ANNOUNCER: But longer-term data shows different results.
SAMUEL KLEIN, MD: But these have been short-term studies, six months long, and one study that went on for one year suggests that both groups have the same amount of weight loss at the end of one year because of the marked weight regain in the Atkins diet subjects.
ANNOUNCER: So what's a heavy person to do?