Halloween is here! Tomorrow you'll put on your costume, and head off to costume parties and parades. Some of you will go trick-or-treating in your neighborhoods, walking from door to door to visit people you know and pick up gobs of candy.

You can't wait, right? That's how Jack feels. He's going to be a box of crayons this year, a costume he's worked hard to build. He's got a bag to collect his loot, and he's looking forward to getting home to divide all the candy up into different piles -- one for lollipops, one for M&Ms, one for gum, one for candy corn.

All that candy can be pretty tempting. At this time of year, you can't walk into a grocery store without seeing displays of goodies as tall as you are. And yet your parents and your dentist and your teacher and your doctor have probably all told you that candy isn't good for you.

For many families, holidays like Halloween, Thanksgiving, Christmas and Hanukah are times for special celebrations. Special food treats containing sugar are often part of these events.

Almost everyone likes something sweet every now and then -- but have you ever wondered what sugar does in your body? Experts say that each person in the United States eats about 94 pounds of sugar every year. Sugar tastes good -- but 94 pounds of it is much too much.

Your body has a built-in taste for sugar. Scientists believe that small amounts of sweets help you eat well by stimulating your appetite. But it's a good idea to keep your desire for sugar under control.

Sugar provides quick energy. But for some people, gobbling down a candy bar when they're really hungry can have weird effects. They may get a little jumpy, or excited. And before long they may start feeling tired and hungry. Maybe you've noticed this happening to you.

To survive, you need a combination of different substances found in food. From your food, you soak up nutrients. There are six kinds of nutrients: carbohydrates for fuel; proteins for growing cells, the tiny building blocks of your body, and for repairing damage; fats to protect your cells and serve as a back-up energy supply; vitamins and minerals to keep your body's chemical activity in balance; and water to help carry the other nutrients to your cells. People need to consume all of these groups to survive.

Food provides chemicals to run your body. Substances in the food you eat, whether it's a roast beef sandwich, a cup of yogurt or a candy bar, enter your system through a process called digestion. Digestion breaks up the chemicals in the food you eat into something your body can use.

Different kinds of food act in different ways in the body. Some foods are digested slowly, releasing chemicals into the bloodstream at a quiet, steady rate. Other foods -- like sugar -- rush into the bloodsteam and start going through your body right away.

You need carbohydrates, which are found in things like bread, potatoes and milk as well sugary foods, for immediate energy. Your body turns carbohydrates into glucose. When glucose combines with oxygen from the air you breathe, the result is energy.

Sounds great, right? But it's not enough. If you tried to live on carbohydrates alone, you'd soon begin to get sick.

It's the combination of all the nutrient groups that keeps you going. So while it may be fun to think that you'll spend the next week eating Halloween candy and nothing else at all, you'd soon discover that it wasn't as much fun as it seemed. Sweets do provide energy -- but they don't contain all the nutrients you need.

Halloween is fun for lots of reasons, and candy is one of them. But tomorrow, when you go trick-or- treating, remember your ordinary supper. Its mixture of nutrients gives you the exact combination you need to have the power for strutting through a parade, bobbing for an apple at your class party, or racing down the block to meet your friend the ghost for an evening of trick-or-treating. Tips for Parents

"At Halloween, parents should be concerned about tainted treats," says Anne Coulter of the National Safety Council in Chicago, "but they should also remember that a worse danger is from pedestrian accidents." The Council recommends the following procedures for this holiday:

Buy or design a costume in which your child can move safely and easily. It should be light-colored, flame-resistant and large enough to wear over warm clothes.

Use painted-on facial decorations, or make certain that tie-on masks have holes large enough to let your child see clearly.

*Insist that trick-or-treaters carry flashlights, cross at intersections and walk on the sidewalk.

*Don't allow trick-or-treaters to carry sharp objects.

*Don't allow kids to eat treats along the way. Serving a good meal before they go out can help accomplish this. At home, inspect all candy. If you have any suspicion at all about the treats, throw them away.

*Trick-or-treat only in familiar neighborhoods, at well-lit houses. Never enter any home or apartment. Never allow a child to trick-or-treat alone.