[header] How to lose weight in 3 weeks [title] Skip fad diets. [step] Fad diets may lead to some immediate results, but they're rarely healthy, and the results never last. Fad diets typically mean a gimmick that doesn't include a well-balanced diet. 
You miss out on key nutrients over the course of the diet. Most people immediately put the weight back on after concluding the fad diet as well.