I have read many threads here and have heard it over and over from all types of health people that losing so much weight is not healthy for your body. But, how come you can find many examples, such as the Biggest Loser, where people have been successful in keeping it off, after losing 100+ pounds in a few months? Everyone says it should be a pound or two a week. I know that some contestants have relapsed, but a quick websearch reveals that quite a few of them have successfully kept it off. If you are mindful of your calories, approximately how many you are burning and how many you're expending, then why is it bad for a big man or a big woman to do a lot of activity on low calories? There's a forum on Men's Health and out of interest I looked on there and there were a number of regular guys who had lost large amounts of weight in less than a year and have still kept their new physique. Is the conventional wisdom bull, or is there still something to it?