Deborah George, age 15, of Monroe, La., for her question:

HOW MANY CALORIES DOES A PERSON NEED DAILY?

The number of calories a person needs each day depends on the person's sex, age, body build and degree of physical activity. A husky professional baseball player, as an example, needs a lot more calories each day than does a slightly built computer operator.

Nutritionists say a moderately active man of average weight needs about 3,000 calories each day. A moderately active woman of average weight needs about 2,200. Children vary depending on age, weight and activity from between 850 to 3,000 calories.

Daily calorie consumption or intake by all people in the poorest developing countries averages under 2,000    far less than most people require. In many developed countries,  dail  r   caIorle           ¬consumption averages well over 3,000 calories    far more than most people need.

Calorie is a unit used to measure heat energy. Scientists measure the amount of heat produced with an instrument called a calorimeter.

One of the most important uses of the calorimeter is to measure the amount of heat given off by different foods when they burn. This measurement tells how much energy a certain food has when it is completely_used by the body.