To attain incredibly low body fat levels quickly, many all-natural, professional bodybuilders use a few simple dieting concepts that remain relatively unknown to the general public. You DO NOT have to be a bodybuilder to get great results from these techniques. If you just need to lose a few pounds, then you will probably not want a diet that is too extensive. Often times, they will gain back more than they lost. This is a consequence that most people do not consider.
Most people usually start gaining weight again.
You will most likely go back to your old eating habits. You cannot remain on that type of diet forever, and sooner or later you will have to face real food again. They do not prepare you for this. Most fad diets work. The question is only how long can you maintain the results.