Maintaining a healthy weight is all about caloric balance: balancing calories taken in through your diet and calories expended during exercise. If you take in (eat) more calories than you expend, you will gain weight. If you expend more calories than you eat, you will lose weight. If you match energy intake with energy expenditure, you will maintain weight. Some useful Web tools can help you calculate your energy balance. Visit caloriesperhour.com or the Beehive.