Most patients can actually lose weight eating 2000 calories of protein and fat a day, although I don’t recommend it. You’ll lose faster on 1500 calories of protein and fat a day, but you’ll still lose on 2000. You won’t lose any weight on 2000 calories of protein, fat and carbohyrate a day – but if you completely eliminate carbohydrate (eat just protein and fat), you’ll be surprised how many calories you can eat and still lose weight. Exercise is a double edged sword as it increases appetite, but if you stay on a low carbohyrdrate diet and exercise (without increasing your calories), you will lose weight faster. The trick is not to increase calories while exercising, as exercising can throw you into feeding frezny. It’s way too easy to eat more than 3000 calories of protein and fat a day, if you are working out. But if you limit your protein and fat calories to 2000 a day, and exercise, you’ll lose weight.