At least five studies in the last two years showed that low-calorie meal replacements are among the best ways to lose weight and keep it off. Lifestyle changes are much easier if you don't have to think about them. Drinking a weight loss beverage is simpler than cooking a low-calorie meal at home. The real key to weight loss is keeping the weight off permanently. That's not so easy. Most long-term weight loss studies show a one-year success rate of around ten percent. However, several studies in the US and Europe have had resounding success with diets based on meal replacements.
University of Nevada, Reno, researchers found that weight loss programs that used meal replacements worked just as well as programs led by nutritionists that did not use the meals. Keep it simple when you're trying to lose weight. The less you have to think about preparing meals the more willpower you'll have.
(Obes Res., 9 (Suppl. 4): 312s-320s, 2001)