Calorie requirements are unique to each person based on factors such as age, gender, weight, height, body composition and activity level. The average adult female -- 40 years old, 5 feet 5 inches and weighing 140 pounds -- and who maintains a healthy weight burns about 1,600 calories a day. The average adult male -- 40 years old, 5 feet 10 inches and weighing 170 pounds -- who maintains a healthy weight burns about 2,200 calories a day.