The answer is simple...fad diets are not natural. It encourages fast weight loss (usually within 10 days to 1 month period) through unsafe and unrealistic methods. Besides, fad diets often exclude physical activity in the program, which is essential in the process of weight loss. Weight is gained right back after because people return to their old eating habits and lifestyle. One should be caution of diets recommending a certain nutrient or combination of foods to encourage fast weight lost.
However, fad diets are popular because many of them do work for a short amount of time. Besides, many people prefer to try the quick fix of a fad diet instead of making the effort to lose weight through long-term changes in their eating and exercise habits. In many such cases, weight loss is due to removal of certain types of food or whole food groups or focus mainly on one food in particular. All restrict food in some form, therefore fewer calories are consumed as one normally would. However, it’s likely that much of the weight you lose is from water and lean muscle, not from body fat. As a reaction to the starvation process, your body will start working in order to keep up with the energy needs. However, if fats are not burned and is avoided in the diet, the body will preserve the fat that is has in store. If this condition persists, stored fats will be burned, and the dieter will start getting weaker and will not be able to perform his normal duties because it requires more effort and time for body to produce energy from fat rather than from muscle. Also, most people are not able to keep up with the demands of a diet that strictly limits their food choices or requires them to eat the same foods over and over again. People who use fad diets usually end up gaining back any weight that they initially lost.
One must know that the first step in losing weight safely and permanently is to understand that there is no magic potion or quick fix to permanent weight lost. Lifestyle changes should be made that this encompass healthy eating (food containing appropriate number of vitamins, minerals, proteins, carbohydrates and fats), consistent exercise and eating food that are not conducive to weight lost moderately.