The amount of calories needed to keep a body functioning varies widely from person to person. According to Fitness Blender, a 5-foot-tall, 35 year-old-woman weighing 130 pounds needs 1,338 calories, while a 20-year-old, 6-foot-tall man weighing 180 pounds needs 1,966.
A simple formula for determining a rough calorie count needed for an individual doing nothing is body weight x 11. Fitness Blender provides an accurate formula that is much more complex. Calorie count for sedentary individuals is very low. Although the body needs energy to maintain simple functions like brain activity and breathing, much more energy is required when physical activity is added.