In order to lose weight, you need pretty darn severe calorie restriction, or you’re not going to lose weight fast enough and consistently enough, to keep you on your diet. Rule of thumb is if you’re eating much more than 1500 calories a day, you won’t lose weight fast enough to stay motivated. Fast weight loss makes the deprivation worthwhile. Slow weight loss is not reinforcing enough to keep you dieting. Slow weight loss does not retrain your eating habits or shrink your stomach. It just prolongs the agony.