We do not get fat because we eat too much (although many do). If that were the cause, other species with an ample food supply would also get fat -- yet they don't. In fact, the only animals in their natural environment who are genetically disposed to put on fat are those whose food supply is not guaranteed.
Surely everyone who has lost weight by starving (which is what low-calorie dieting is) only to put it back on again, must know that 'dieting' does not work.
It doesn't work because it is unnatural.
Many animals, including us, have evolved the ability to store energy as fat in case of times when food is scarce. If we do not eat enough the body fights to retain fat. For this reason low-fat, low-calorie dieting forces our bodies to conserve energy -- it is a recipe for weight gain.
The way to lose weight is firstly to eat as much energy as your body needs, and secondly to eat foods that we, as a species, have evolved and are genetically programmed to eat.
When a friend, who has been on and off diets for most of their, says: "do you mean you have been dieting for thirty-six years?" The answer is, "No, we have been eating normally for thirty-six years!"