In the vast majority of cases, the "diets" themselves are not recommended by nutritionists when you want to lose weight. Because the diet is usually followed for a short time ... then, gradually, the person finds his old eating habits. Moreover the body, being in caloric restriction, will begin to "save" its caloric expenditure ... After a while, the risk is an increase in weight. What is called the yo-yo effect (weight loss-weight gain).
In fact, in case of overweight, from a dietary point of view, it is recommended above all to change certain eating habits and to stick to it, avoiding to engage in draconian diets. In addition, regular physical activity is recommended. The goal must be reasonable, but achieved! Already losing 10% of its initial weight is considered a good result by nutritionists, and especially it will reduce the health risks of overweight.
Sources: Mayo clinic diet manual, 5th edition, Hardback, 1981. The Clic diet Mayo, Good boks, 2009, Afssa