Roller coaster dieting (sometimes called yo-yo dieting) is a nasty cycle to get caught up in. This is a cycle where a person tries a weight loss diet for a while, loses weight, then goes off the diet. This is the down part of the roller coaster and it can feel pretty good, but it doesn't stop there. Once off the diet, the person not only goes back to their original weight, but adds on a few extra pounds. This can wreak havoc on the mind and body, and is not healthy. So, why does this happen? There are a lot of specific answers, but they all come back to one thing: the diets themselves are to blame, not the dieters.