I agree that these diets can instill confidence that it's possible to lose, since I think that anytime you reduce calories to an extremely low amount you're bound to lose. For example - anyone would lose weight eating only one slice of whole grain bread per day, but it's certainly not helping them healthwise. Even if you move on to healthier eating from there, you're increasing calorie intake which will likely put you into a major stall - which deters most from continuing. Thus the fad-diet roller coaster. It may be slower, but healthy eating with realistic calorie amounts is, in my opinion the only way to naturally obtain "continued fat loss and life-long health".