Students at Melwood Elementary School in Upper Marlboro learned a lesson in healthful eating and exercise April 25 from a somewhat unlikely source — a really big piece of chocolate.

Chicago-based chocolate company World’s Finest Chocolate, whose creations often are used by schools and other nonprofit organizations in fundraising campaigns, is touring more than 75 schools throughout the country — including three in Maryland — with the world’s largest chocolate bar, which weighs in at more than 12,000 pounds.

Principal Kristil Fossett said her school was chosen partly because of its participation in two World’s Finest Chocolate fundraisers this school year. Melwood Elementary was the only school in Prince George’s County to be chosen for a visit by the giant chocolate bar.

Tour director Sarah Lynn Brannan said the gargantuan treat — which contains 5,000 pounds of sugar and, according to recommended serving sizes, can feed more than 200,000 people — is intended to get children’s attention and then teach about proper proportions of foods to eat.

“The big bar makes it more memorable. We don’t want them to forget what we tell them about portion control,” Brannan said, adding that they also “give them a chocolate sample of the correct portion size, as well as a jump rope.”

As of 2008, more than one-third of children and adolescents in the United States were considered obese or overweight, according to the Centers for Disease Control and Prevention.

Shakira Pitts, 10, of Clinton said although the giant chocolate bar “looks delicious,” she learned the importance of maintaining a healthy lifestyle.

“If you eat a lot of something, it’s not good, so you should try to shorten it down and either save some [chocolate] for later or share it with a friend,” the Melwood Elementary fifth-grader said.

Before catching a glimpse of the bar, which was certified as the world’s largest by Guinness World Records in September, students watched a video about the importance of eating healthfully and correct portions and exercised by way of some dance instruction.

Fossett said after the event she was pleasantly surprised by the “energy” of the presentation.

“I looked at our scholars and saw them actively engaged in the presentation,” she said. “I saw some reflection on their faces about the way they eat and things they might do differently.”

Alexandra Sanders, 10, of Upper Marlboro said she learned it is important to exercise regularly in addition to eating healthfully.

“If you want to stay fit, first you have to exercise,” the fourth-grader said. “It’s okay to eat chocolate, but you just have to eat the right amount.”

Sheila Nedd, a special education teacher and Melwood Elementary’s coordinator with the Alliance for a Healthier Generation — a Portland, Ore.-based nonprofit organization focused on stopping childhood obesity — said the event did a good job of ensuring students understood there needs to be a balance in their diets.

“The bar got their attention,” Nedd said. “By showing such a large item, the kids think, ‘Oh, let me see that.’ But then, they tell them that just because it’s a big huge bar, you should be eating small amounts.”