Have you noticed that just about everybody is getting bigger these days?

And, no, they're not just growing taller. Turns out that 9 million kids, ages 6 to 15 years -- that's about 15 percent of you -- weigh, well, way too much. Since 1980, the number of overweight children and teens in the United States has tripled, the government reports.

So what's the big deal?

Just this: your health.

By piling on the extra pounds, kids are starting to develop some diseases that used to be problems only for adults, including high blood pressure (which makes your heart work harder to pump blood through your body and can damage your blood vessels); high blood cholesterol (too much of a bad kind of fat in your blood, a condition that can harm arteries); and Type 2 diabetes (where your blood sugar rises too high, which can damage the kidneys, blood vessels and eyes). Of course, eating too little food isn't healthy either: You've probably heard about Mary-Kate Olsen and her recent treatment for an eating disorder known as anorexia -- eating so little food that you can get sick.

As you head back to school, you'll perform best -- and be able to have more fun -- if you can find the right balance of eating great-tasting healthy food and moving more throughout the day to help you burn calories. And guess what? It can be fun. Sally Squires provides some tips for making smart -- and delicious -- choices.

Food to Pig Out On

Baby carrots, slivers of red pepper, slices of juicy apples, pears, bananas, a handful of grapes, watermelon, chunks of pineapple, berries and crispy celery spears. These are a few of the great-tasting fruit and vegetables that are low in calories (which means you can eat a lot of them) and provide vitamins and minerals that will help keep you healthy and growing.High-Energy Food

Eat half a peanut butter and jelly sandwich (made with whole wheat bread for extra staying power) after school to help keep you going from classes through soccer practice. Raisins and nuts also are high-energy. So is string cheese. An energy bar or granola bar is another good choice. Or make your own high-energy trail mix: Take about a cup of your favorite unsweetened cereal (Cheerios, Chex, bran flakes, corn flakes, Rice Krispies), add a small box of raisins (or a quarter cup of your favorite dried fruit) and a quarter cup of nuts, soy nuts or chocolate-covered soy nuts. Put in a plastic bag and shake to mix. Divide into two smaller bags. Enjoy!Great-Tasting Snacks

Popcorn, pumpkin pie and peanuts are three good choices. Also very tasty: applesauce or hummus with whole wheat crackers. Or have a bowl of your favorite unsweetened cereal with some skim milk. It's not just for breakfast, you know! Bone-Building Food and Drink

Go ahead, dig into that yogurt. Drink a glass of milk (you can even add a little chocolate syrup, if your parents say it's okay). Or have a slice of cheese on your sandwich. Milk and other dairy products, including pudding and smoothies, not only taste great, but they help build strong bones because they have calcium and Vitamin D. If milk doesn't agree with your stomach, ask your parents to get orange juice or soy milk with added calcium.We Dare You!

In Japan, people are urged to eat 30 different foods a day to stay healthy. Sampling a new food, even the ones that look weird or smell different, is a great way to add variety -- and a little adventure -- to your life. So we dare you: Try a new food or drink once a week, even a bite, just to see if you like it. Then write to us and tell us what you've discovered: leanplateclubkids@washpost.com.