The goal is to consume as many calories as you can while still losing body fat and maintaining or gaining lean muscle. If your calories are already below normal, don’t restrict them further. Instead stick with your current amount and focus on becoming stronger and more active, so you can gradually increase your calories to a normal healthy level. If your calorie intake is already in a healthy range, decrease it only slightly, and only if necessary. A small reduction of about 250 calories a day, or 10-15 percent less than usual, is more likely to protect your lean muscle and less likely to trigger a slow-down in your metabolism.