Your weight has been important since the moment you were born. Maybe you even know what your birth weight was. Most babies weigh less than 10 pounds and sometimes as little as 3 or 4 pounds.

But very quickly, a young baby gains weight and everyone is glad about that because it means the child is growing bigger and stronger.

As you get older, your weight is still important. It's something your parents and doctor will probably keep an eye on. When you go for a checkup, the doctor often will record your height and weight and compare it with what it was the last time you came in. The doctor wants to check that you are a healthy weight because weighing too much — or too little — can be a problem.

But these days, being overweight is more common than being underweight. In the last 30 years, a growing number of kids and teenagers have developed weight problems. Today, 1 out of 3 kids and teens between the ages of 2 and 19 are overweight, or obese (a word that means very overweight).

Many grown-ups understand what it's like to have weight problems, since 2 out of every 3 adults are overweight or obese.

For kids and adults, weighing too much can lead to illnesses and health problems. And a kid who is overweight might get teased or find it hard to keep up with friends on the playground.

What Does It Mean?

When people talk about being overweight or obese, they mean that someone has more body fat than is healthy. Everyone has some body fat, but excess fat can affect someone's health and ability to walk, run, and get around, as well as how the person looks and his or her self-esteem.

How Is It Measured?

Someone can be underweight, at a healthy weight, overweight, or obese. There is no one perfect weight for a kid to be, but there are healthy weight ranges for kids based on height and gender (whether the person is a girl or a boy).

Doctors use four categories to describe a person's weight:

1. Underweight: A person weighs less than the healthy range for his or her age, gender, and height.
   
2. Healthy weight: A person's weight is in the healthy range for his or her age, gender, and height.
   
3. Overweight: A person weighs more than the healthy range for his or her age, gender, and height.
   
4. Obese: A person weighs much more than the healthy range for his or her age, gender, and height.

BMI

But being overweight is more than a number on the scale. A doctor is a good person to help determine if a kid is overweight. The doctor can look at a kid's ideal healthy weight range while also taking the kid's height into account. A taller kid naturally could weigh more than a shorter kid and not be overweight.

Perhaps the best way to assess a kid's weight is to use something called body mass index, or BMI.

BMI uses a kid's height and weight in a calculation that results in a number. That number can be plotted on a chart that also considers the kid's age and if the kid is a girl or boy. BMI is an indicator of how much body fat the person has, but it's only an estimate.

Because muscle weighs more than fat, it's possible for a muscular person to have a high BMI, but that doesn't mean he or she has too much body fat. Likewise, it's possible for someone to have a low or ideal BMI but still have too much body fat.

You may get a BMI report from school, but the best way to understand BMI is to talk to your doctor.

Why Do People Become Overweight or Obese?

Most of the time, people have too much body fat because the body gets more calories (from foods and drinks) than it burns through physical activity, such as playing soccer or walking to school. Extra calories are stored as fat. The more extra calories a person consumes, the more fat is stored.

This happens very easily in modern life. People spend more time in front of TVs or computers and less time exercising. We drive everywhere instead of walking or riding bikes. Fewer schools offer gym classes every day; more kids play video games than active games like dodgeball.

Even grown-ups spend more time sitting at desks and in cars than they once did. Most people are not getting enough activity and exercise. People also lead busier lives so they have less time to cook healthy meals. We eat more restaurant meals, take-out food, and ready-made food from a box.

Weight problems also can run in families, but don't let that discourage you from making changes that could help you reach a healthy weight. Your habits — what kind of food and how much you eat and how much you exercise — can make a big difference.

How Can Excess Weight Hurt Your Health?

It's hard to feel good when your body has too much weight to carry. Being overweight or obese can make it harder to breathe and sleep. It can make a person feel tired and cause aches or pains. A weight problem also can make you embarrassed, sad, or even angry. And when people feel bad, they may eat more because food can be comforting. This isn't a good idea, especially if someone is already overweight.

Getting help is important because weighing too much can make you sick. Overweight or obese kids have a greater chance of getting type 2 diabetes and other health problems. And later in life, they have a higher risk of getting heart disease.

How Can You Keep From Becoming Overweight?

One of the best ways to stay at a healthy weight is to be active. You can join a sports team. Or, if you don't like team sports, try swimming, tennis, martial arts, or just being active in your own backyard. Jumping rope, dancing, and running around will get your heart pumping.

Getting some extra exercise can be as easy as taking the stairs instead of the elevator or walking instead of having your parents drive you. Being active also means watching less TV and playing fewer video games.

Eating healthy is another part of staying fit. Aim to eat a variety of foods and get five servings of fruits and vegetables a day. Choose water and low-fat milk over soda and other sugary drinks. When it comes to high-calorie and high-fat foods, eat them only once in a while and, when you do, have smaller portions.

What Should You Do?

Talking to a parent is the best first step if you are concerned about your weight. Your mom or dad can make a doctor's appointment for you. The doctor may suggest ways of changing your eating and exercise habits.

In general, kids don't need to diet. But a kid who is very overweight may need some expert help from a dietitian or a doctor who specializes in weight management. Together, along with your family, you'll be able to come up with a safe and healthy plan that should include eating nutritious foods and exercising regularly.

Helping Others

If you have a friend or relative who is overweight, remember to be kind. He or she is probably well aware of the problem. Jokes or teasing will make the person feel worse. Try to be encouraging instead by exercising together and sharing what you know about eating healthy foods. Do that and you will both like what you see when you look into the mirror!

Reviewed by: Mary L. Gavin, MD
Date reviewed: September 2011