Different people need a different number of calories every day. Your daily calorie requirement depends on your age, your body size, your lean body mass, and your activity level. In general, you need more calories than an adult your size does. That's because your body is constantly changing and growing. Girls and boys have different calorie needs too.

Most girls need about 2,200 calories a day. Your personal daily calorie requirement may be different if you haven't started puberty yet or if you are in the middle of a growth spurt. Listen to your body. If you feel hungry, eat! back to top

The calorie–weight connection
Your body stores excess fuel as fat when you eat more calories than you burn off through physical activity or metabolic functions like breathing and digesting food. Unfortunately, our bodies have an almost unlimited ability to store fat. When you don't burn off that stored fuel as fast as you consume it, you gain weight.

Not eating enough food can be as harmful as eating too much. When your body doesn't have enough fuel to burn, it goes into starvation mode. In addition to losing weight, you may have irregular periods or stop menstruating altogether, a condition known as amenorrhea. Concerned about starvation mode? Check out anorexia. back to top

How can I tell if my weight is normal?
Keep in mind that it isn't the numbers on the bathroom scale that determine whether or not you're healthy. The key to good health is the proportion of fat in your body to lean body mass. This is called your body composition.

A girl who stands 5'4" and weighs 110 pounds can actually look and feel thinner than a girl who stands 5'4" and weighs 100 pounds (that's 10 pounds less) if her body has a greater percentage of muscle than fat. That's because muscle weighs more than fat.

Because keeping track of your weight is not a good way to measure how healthy you are, focus on your body composition and use the body mass index calculator instead. A girl can't live by scale alone. back to top

Calories and exercise
If you eat a balanced diet, it will be easier for you to meet your daily calorie requirement without having to count calories. Worried about being overweight? Shift the balance to eating more vegetables and fruits and fewer fats, oils, and sweets. To learn more about what to eat each day, check out the MyPyramid.

And get moving! The number of calories you can eat without gaining or losing weight depends on how often you exercise, how long you exercise, and how hard you exercise. Regular exercise can even increase your ability to burn calories while you rest. The more lean body mass you have, the more calories your body burns.

It is easy to fall into the trap of thinking that calories are bad. But getting the right amount of them is essential for energy, good health, and looking and feeling your best. back to top