You will fail when you go on a diet for weight loss purposes. This is because if you are dieting to lose weight, you inherently believe there is something wrong with you. Your self-esteem is compromised, you feel unworthy of x, y, z because of your weight. This creates an interesting paradox where eventually the going gets tough, the cravings kick in, you’re feeling deprived, your brain will say, “What’s the point anyway?” Since your self-worth is already low, there’s no incentive to continue. So you eat.