When Kyle Troka makes trips to the grocery store, he often checks food labels for their calorie content. The senior in Engineering lifts weights and tries to take in as many calories as possible, he said. Claire Fleming, junior in Education, on the other hand, tries to limit her intake of calories by buying low-fat foods and avoiding high-calorie products, she said. Both habits are examples of the diverse functions of calories.

President Barack Obama’s health care reform act, which went into effect last March, included menu labeling regulations. The rules mandate that larger food chains list the calorie content of all menu items. This does not include non-Food and Drug Administration-regulated items like alcohol.

While the act makes food stores responsible for providing the information for the public to make smart eating decisions, some students admit they are not 100 percent sure of what calories are or how they work.

“I know what they are on the label, but I have no idea what they are in general,” Fleming said, adding that she still tries to stay under a limit.

Calories provide energy to the human body and can have positive or negative effects, said Manabu Nakamura, associate professor of biochemical and molecular nutrition in ACES. The body uses calories to perform basic functions, he said.

“Whenever you are doing anything, you need energy,” Nakamura said. “You need gasoline to operate a car — same as calories (are used) to maintain our daily activities.”

If a person consumes too many calories, however, the excess calories become fat. This is a major concern for many health-conscious people and is a contributing factor to weight issues like obesity,” Nakamura said. This happens when calories that could be used for energy are not fully expended, he said. Because of this, the amount of calories one person should consume each day varies.

Estimated Energy Requirements (EER) are used to determine the amount of calories a person should consume. A college-age male may have a higher EER than an active female, Nakamura said.

Most daily values on nutrition labels are based on an average calorie diet of 2,000 calories, Nakamura said. Depending on various factors like age, weight and sex, a person’s EER can be higher or lower than this number. The public should then use the labels as a guide, he said.

Umesh Nathani, 26, of Champaign, said he doesn’t know his exact EER, so when he watches his calorie intake, he uses the 2,000-calorie diet as a personal guide.

“I kind of assume that that’s just about what a person should consume,” Nathani said.

The exact formula used to calculate EER incorporates a person’s age, physical activity level, height, weight and gender. The U.S. National Academy of Science’s Institute of Medicine lists the estimates using the Dietary Reference Intake table, which can be accessed on its website.

Some students, like Troka, still prefer to use their own rough estimates. Troka, who works out at least five days a week, said he just tries to get as many calories as he can. His daily goal is usually 3,000 calories, he said.

“My metabolism is pretty fast so I just try to get in as much as I can,” Troka said. “If I’m looking at a PowerBar or something like that, I’ll look at definitely what’s going to give me the most calories, but if it’s got too much sugar, I try to not eat it as much as the other ones.”

Troka added that restaurants listing calories on menus does not affect his choices. Fleming and Nathani, however, said they think the listings are good guidelines and would deter them from buying certain items at restaurants.

“The rest is your decision,” Nathani said. “You can go on to have whatever you want, but it’s good to have knowledge about what you’re eating.”

Other important factors should also go into such eating decisions, Nakamura said. Nutrients such as protein, vitamins and fiber are important in maintaining a healthy diet, Nakamura said. While simply avoiding calories can still leave people wanting food, eating protein, for instance, can reduce the feeling of hunger, he added.

“These are very important,” he said. “It’s not just the conscious number of percentage of calories.”