Strictly speaking, diets don't fail, people fail to stick with a diet. Following any reduced calorie diet will result in weight loss. The problem is sticking with it. Unfortunately, most diets have built-in failures which trip up the dieter. Diets go wrong by being too restrictive.
Many conventional diets demand a fairly low calorie intake in order to lose weight.
Although true, for people who have a large amount of weight to lose, reducing their usual daily intake by 1000 - 2000 calories a day is a depressing task. Such dieters feel deprived before even starting a new diet. Even for people with small amounts to lose, cutting their usual intake from 2200 or 2500 to 1200 calories, can be a shock to the system. A quick glance at any women's magazine reveals at least one sample menu for weight loss. Upon comparison, the amounts of food seem very small and usually include uninteresting foods such as yogurt, cottage cheese and chicken breasts.