(McClatchy-Tribune Information Services) -- Michael Gross placed a bunch of ripe bananas in 10-year-old Amani Bass's left hand.

Then, taking back one of the bananas, he explained that the bunch represented the total calories consumed, with the one he removed representing what happens when a certain amount of calories are burned through physical activity.

The banana demonstration may sound simple, but it's effective, particularly at Auburn Montgomery's first Youth Fitness Camp, which is designed to teach youngsters who are entering fourth through eighth grades this fall about the importance of balancing caloric intake and expenditure.

"It's important to understand what we are eating," said Gross, an assistant professor in AUM's Department of Physical Education and Exercise Science.

"Alabama has about 3.2 million adults and about one-third of them are overweight or obese," he said. "That means they are eating more than they are burning."

During the weeklong camp, which kicked off Monday, the boys and girls are learning about how to calculate how much physical activity is required to burn calories in foods they may enjoy as well as how to make exercise more fun for themselves and their families.

The Centers for Disease Control has stated that since 1980, the number of adolescents who are overweight or obese has tripled, and the number of children who are overweight or obese has doubled, Gross said. And inactive lifestyles and poor dietary choices are the two main contributors to this growing problem.

"We need to eat. We need to watch what we eat," Gross said, adding that it's OK to have a treat every now and then. The key is finding the balance between what you eat and what you burn.

Even healthier options can be a problem if you eat a 4-cup bowl of Raisin Bran with skim milk as opposed to the recommended 3/4- to 1-cup serving. Calories -- even those in good foods -- add up, he said.

Kelly Gaston, a graduate teaching assistant in Gross' department, agreed and said you can still enjoy pizza, French fries, ice cream and other foods, but you need to be aware of the calories you are consuming.

"A lot of parents don't really know about calories. It's important to start teaching about healthy lifestyles when the kids are young," she said.

In addition to talking about making healthier food choices and nutrition, campers are participating in a variety of moderate exercise sessions.

After the morning discussion on calorie basics, campers had a fun time in AUM's gymnasium. For one of the activities, the group was divided into two teams, and each team's goal was to throw colorful beach balls onto the opposing team's side of the volleyball net. What seemed like a lot of fun proved to be great exercise as youngsters were in constant motion.

Amani said her mom encouraged her to attend the camp, and she was enjoying it. Although she doesn't eat a lot of candy, it's always important to learn about good nutrition, she said.

Sometimes at home, she helps out in the kitchen, preparing such foods as grilled-cheese sandwiches and peach cobbler. Now, with what she's learning at the Youth Fitness Camp, she might encourage her mom to tweak the recipes to ensure they work in a healthy lifestyle, she said.

"Maybe I can try new things with my mom," she said.

Twelve-year-old Scott Sterling said he, too, was having a good time learning more about developing healthy lifestyle habits. Before this camp, he said he knew people have to be careful about what they eat, but he didn't know much about the science behind it.

"It's good for all kids to know about calories. If they knew more about it, they would know how to eat," he said.

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