A couple of things. Exercise, while wonderful for a lot of things, is not a good way to try and lose weight long term, unless you train like an Olympic athlete. You can't make up for a poor diet with exercise. Weight gain or loss, long-term, is not a matter of calories in - calories out. If you think that it is only a number of calories game, then you believe that your body only cares about how many calories you eat and not what kind of calories they are. Few people would say that was true once it is considered (does anyone think there is no difference to your body whether you eat 1500 calories of chicken or 1500 calories of ice cream?). Long term weight loss or gain is hormonally driven. Insulin's job is to store fat. So if you eat a diet that is high in carbohydrates you are constantly asking for insulin to be produced. If you are eating a low-carb diet, you are not probably paying attention to the amount of calories. For initial weight loss, this is OK, but if you keep eating the same amount of food (typically high in fat), eventually you will reach a weight where the amount you eat supports that weight level. If you are not at your reasonable goal weight, at that point calories do matter. You are typically eating too much cheese or too many nuts because that level of consumption is what you started out with when you began eating low carb. Exercise is very good for maintaining weight loss.