A proper diet is supposed to be a long term solution to living a healthy life.  A fad diet is a short-term attempt at losing weight, and being short-term, its effects are also short-term.  Meaning if fatty doesn't change their diet permanently they are just gonna get(or stay) fat. They lack the willpower to make a permanent lifestyle change, hence all the bitching about diets that don't work.  They've bitched so much for so long, that they have started to change the actual meaning of the word diet.  Think about that one for a minute.