If you exercised constantly for a week when would you start losing weight?

When exercising your body burns a small amount of calories. Its the afterburn that really counts. For 24 hours after you exercise you body is burning more calories and is eating into the fat stores because you have used your reserves while exercising.

If you want to calculate what you need to do to lose a pound a week. Work out your weight in pounds and multiply by 13, this gives you the total calories that your body consumes daily to keep at your current weight. To lose one pound a week your body needs to either burn off or consume less 500 calories a day. One pound = 3500 calories. The 500 calories can be burned off using exercise or cutting back on food. 1 mile of walking or running = 100 calories.