Every body has fat, every body needs fat.

Fat has been given a bad rap, but it is an essential part of a healthy body. Basically, fat is fuel that your body has stored to feed you and your brain. Fat also insulates your body from the cold, regulates your temperature, and covers your internal organs to protect them from injury. back to top

Fuel for thought
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 eat it, you gain weight. If you continue on this path, you may become overweight or obese. These conditions can lead to chronic, long-lasting health problems like heart disease, high cholesterol, high blood pressure and diabetes. Your great aunt may call it baby fat, but overweight kids often grow into overweight adults. back to top

Starvation mode
Not having enough body fat can be as harmful as having too much. When your body doesn't have enough fuel to burn, it goes into starvation mode. True, you may lose weight, but your metabolic functions will slow down, leaving you with no energy, little ability to concentrate, a weakened immune system, and anemia. You may also lose muscle strength in starvation mode. In addition, your skin becomes thin, pale, and furry, and your hair falls out. Even if you aren't seriously underweight, without enough body fat, you may have irregular periods or stop menstruating altogether, a condition known as amenorrhea. And, as your body loses nutrients like calcium your bones age prematurely. Concerned about starvation mode? Learn about anorexia. back to top

Fit and fat
Fat is normal and necessary for good health. You aren't fit if you don't have some body fat.

It's important to keep in mind that it isn't the amount of fat or the numbers on the bathroom scale that determine whether or not you're healthy. The key to good health is the proportion of fat to lean body mass. This is called your body composition. When you know your body composition, you've got a starting point for tracking your health and fitness goals. back to top

What's my body composition?
You can figure out your body composition in a number of ways. The most helpful (and easiest) is to use the body mass index (BMI) calculator. To calculate your BMI, divide your height in meters by your weight in kilograms. Sound like an Olympic event? Don't worry. It's easy. Just plug in your height and weight, and our BMI calculator will do the rest!

Because keeping track of your weight is not a good way to measure your overall health, focus on your body composition and use the BMI calculator instead. A girl can't live by the scale alone. back to top

Which weighs more—a pound of muscle or a pound of fat?
This is kind of a trick question. Although a pound of muscle and a pound of fat both weigh a pound, they are not equal when it comes to your body composition.

A pound of muscle takes up less space in your body than a pound of fat does. So, a pound of muscle looks smaller than a pound of fat. That means you look and feel thinner. Muscle also burns fat more efficiently than fat does. The more muscle your body has, the more powerful is its fat-burning engine.

On the other hand, muscle is denser than fat so it weighs more. A girl who stands 5'4" and weighs 110 pounds may actually look 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. back to top