losing weight is ALL about calories. You have to burn more than you eat. It's as simple as that. You can actually calculate exactly how much you will lose if you eat a certain amount of calories. I eat 1300 calories a day. I weigh/measure EVERYTHING i eat. Ive been doing this since february 1st and have lost 16 pounds so far. I haven't went to the gym yet, but i will incorporate that into my routine next month.