The Zone Diet is based upon your individualized protein requirements. These are derived from your lean body mass and your levels of physical activity. Once those are established, the levels of protein you need to maintain your muscle mass are evenly spread throughout the day just like a drug. The amount of protein at a meal determines the amount of carbohydrate needed to stabilize blood sugar levels for optimal brain function. Finally, you add a dash of monounsaturated fat to complete the meal. Following these requirements, the average female will consume approximately 1,200 calories per day and the average male will consume approximately 1,500 calories per day without hunger or fatigue since you are stabilizing blood sugar levels in the blood and reducing inflammation in the hypothalamus.