New London — Fifth-grader LizValarie Velez stood at the front of the classroom, holding a 16-ounce glass of seltzer, as classmates Amarianna Manso and Nayara Gonzalez scooped in the white crystals, a teaspoon at a time.

“We need seven more. Keep going,” said Lucy Lyman, the Food Corps service member giving the lesson in Margaret Lewis’ fifth grade class at Jennings School on Thursday.

The class of 27 students giggled as the two girls added more sugar. Velez stirred the mixture.

“So we put in 16 teaspoons of sugar,” Lyman told the class. She reached into her bag and held up a 16-ounce bottle of Coke.

“This bottle of Coke has the same amount of sugar that we just put in the glass,” she told them. “Would you guys want to drink that?”

Some of the students laughed. “Yes,” others said.

But Lyman wasn’t deterred. She went on to tell them that for their age, their daily sugar intake should be limited to three teaspoons.

Her lesson about the amount of sugar in common beverages and processed foods, the harmful effects of excessive sugar and how to read labels, which she will give several more times to other classes before the end of the year, is a key part of the message promoting healthy eating among youth that is the main mission of Food Corps, a national initiative.

Emphasis on reducing sugar intake is also a main focus of the U.S. Department of Agriculture’s new dietary guidelines, released last month.

“Natural sugar in fruit and dairy products is good for us,” Lyman told the class. “We can eat natural sugars all day.”

But not so with added sugar — whether from regular sugar, high fructose corn syrup, or some other sweetener. And, Lyman told them, it’s hidden in many foods.

“It’s in salad dressing, ketchup, granola bars and barbecue sauce,” she said, holding up a bottle of salad dressing.

“I like eating ketchup,” one boy called out.

To further emphasize her point, Lyman passed out bottles of Gatorade, iced tea, Red Bull, orange soda and other sugary beverages, then taught them how to read the labels use their math skills to calculate how many teaspoons of sugar they’d be ingesting if they drank it.

A 32-ounce bottle of Gatorade fruit punch, for example, held a whopping 14 teaspoons of sugar.

Vitamin Water, marketed as a healthy drink, delivers eight teaspoons per serving.

“That’s worse than Red Bull,” Lyman told the class. “And it’s supposed to be good for you.”

In a similar example, Lyman asked the class to guess which had more sugar — a serving of Pillsbury chocolate fudge cream frosting, or a serving of Nutella spread.

The answer: Nutella, which has 21 grams (seven teaspoons) of sugar per serving, compared to 18 grams (six teaspoons) for the frosting.

“That’s why it’s really important that we read the labels to find out what’s in our food,” Lyman said.

By the end of the lesson, Lyman had some converts — at least for the moment.

“What does sugar do for us?” she asked.

“It gives you a sugar rush,” replied Eric Butler.

“But then you get droopy,” Lyman said. “It’s not sustained energy.”

They talked about getting cavities. One girl said eating sugary foods makes her want to eat more sugary foods.

“So it’s addictive,” Lyman said.

“It gets you fat,” offered Kmara Royster. “You gain weight.”

Lyman didn’t advocate an all-or-nothing approach, but moderation. She urged students eat more fruits and vegetables and less sugar, and to pay attention to what they're putting in their bodies.

“You can still have sugar, just smaller amounts,” she said.

Daneysha Cortes liked that message.

“If you’re going to eat chocolate, eat a small portion of it,” she said.

“What else can you do?” Lyman asked the class.

“Eat lots of bananas,” offered Mya Rodriguez.

j.benson@theday.com

Twitter: @BensonJudy