The obvious way of losing that “freshman 15” in no way exclusive to freshmen may seem like eating less, but what about considering that other activity so common among college students — drinking.

“People have no idea how many calories they’re consuming when they’re drinking. And it’s a whole lot,” said Kelly McCarthy, a senior marketing communication major who bartends at Foundry on Elm, a casual bar in Davis Square.

According to the National College Health Assessment and Emerson’s Health and Wellness Center, 24% of students asked had one to two drinks, and 34% had three to four drinks, the last time they socialized in the past 30 days. The same survey shows that 22% of students consumed alcohol six to nine days over the last 30.

According to its label, an eight-ounce Pepsi bottle contains 100 calories, and 1.5 ounces (a shot) vodka contains approximately 69 calories. So if you drink two of these 169-calorie drinks a night, six times a month, that adds up to 2,028 extra calories per month.

“There are a lot of calories in alcoholic drinks that people don’t know about. And honestly, I think that if people knew, they wouldn’t care that much because they drink to have fun,” said Shakala Alvaranga, a freshman broadcast journalism major. “I think that the amount of calories in it is sickening and will hurt people who drink in the future, so it’s something that people need to be aware of.”

So how do you minimize the amount of calories you consume while drinking? According to McCarthy, the alcoholic drink with the fewest calories is a vodka soda, pure alcohol mixed with a calorie-free club soda. Another simple solution is a “straight” drink, so just the alcohol itself. “Cocktails have so much empty sugar in them. They’re really bad for you. Anything with cream, sour mix, or simple syrup is just so bad,” said McCarthy.

If you’re looking for a drink low on calories, McCarthy suggests opting for fresh ingredients, such as lime juice, instead of juices full of concentrate, like cranberry or orange juice. The trick is to muddle the drink with fresh juice instead of mixing with something sugary, like simple syrup, which is half water, half sugar, she said.

Some, however, are conscious of the sugar and opt out of it. “I usually don’t drink things with a lot of sugar, so I’m not worried about it now. But in the future, when I’m more health conscious, I’ll probably worry about it,” said Lauren Foley, a sophomore visual and media arts major.

In terms of light beer, McCarthy suggests choosing one you enjoy the most instead of being calorie-conscious because the calorie counts only slightly fluctuate between them.

McCarthy has been bartending for four years. In Massachusetts she has worked at Remington’s on Boylston Street and Foundry on Elm in Davis Square, but she has also worked in Miami. McCarthy said that she worked her way up to being a bartender instead of attending a bartending course. She worked as a hostess and a waitress, before asking to apply for the bartending position. “Every time they’d make a drink I’d watch and ask ‘Why are you making that? What is that?’ and after a while there was an opening and I applied,” she said. Though she does not have a signature drink, many drinks McCarthy serves are classic drinks with a “Foundry” twist.

“You probably shouldn’t be drinking if you’re on a diet,” McCarthy said. But the next time you feel like ordering a Margarita or a vodka cranberry, keep in mind that the calories will haunt you tomorrow in your hung-over haze.