The only way to lose weight is to burn more calories than you consume! This is the simple key to EVERY effective weight loss program. In order to lose one pound a week you need to have a calorie deficit or 500 calories a day, to lose 2 pounds a week the deficit must be 1000 calories a day (more than that and you will go into starvation mode, where you become extremely tired and stop burning any calories). So how do you know how many calories your burning? For a basic idea you can log onto the dailyplate. If you are interested in the exact number of calories you are burning, you may need to purchase a heart rate monitor or cute little contraption called the Bodybugg, which counts the calories you burn all day.