Diet Programs Approximately 8 million Americans a year enroll in some kind of structured weight-loss program involving liquid diets, special diet regimens, or medical or other supervision. In 1991, about 8,500 commercial diet centers were in operation across the country, many of them owned by a half dozen or so well-known national companies. Before you join such a program, you should know that according to published studies relatively few participants succeed in keeping off weight long-term. Recently, the FTC brought action against several companies challenging weight-loss and weight- maintenance claims. Unfortunately, some other companies continue to make overblown claims. The FTC stopped one company from claiming its diet program caused rapid weight loss through the use of tablets that would “burn fat” and a protein drink mix that would adjust metabolism. The FTC also took action against three major programs using doctor-supervised, very low- calorie liquid diets, and they agreed to stop making the claims they had been making unless they could back them up with hard data.