The amount of food energy you need each day depends on how old you are, how big you are, and whether you’re a girl or a boy.
Children from 6 to 9 years old require at least 2,100 calories a day to maintain good body health. By the age of 12, the body requires about 2,300 calories.
Boys from 13 to 15 need about 3,000 calories per day, and girls that age, 2,500. Boys from 16 to 19 require about 3,400 calories, but girls that age, only 2,300. After that, the number of calories needed per day usually goes down. By the age of 35, a man needs only about 2,600 and a woman, 2,000 calories per day.
By the age of 65, a woman may need as little as 1,600 calories per day, about what is needed by a four-year-old child!