Chapel Hill Mayor Mark Kleinschmidt and Durham Mayor Bill Bell say they will drink at least 60 ounces of water a day this month as part of the NoFizz Charlotte Mayor's Challenge.

The pair are among 31 North Carolina mayors, including six in the Triangle area, who have pledged to forego carbonation in favor of more water. Mayors in Burlington, Siler City, Fuquay-Varina and Henderson have also signed on.

The commitment will help him stay on a healthy track throughout the year, Kleinschmidt said.

"It goes really well with the annual effort that many of us make at the beginning of the year to recommit ourselves to healthy living," he said.

Kleinschmidt craves a soft drink in the middle of the afternoon, "so this afternoon will be my first real test," he said Monday.

He usually opts for Diet Coke or Diet Dr. Pepper.

Since he became mayor last year, Kleinschmidt said it's been hard to keep a consistent workout routine, but drinking more water has already helped.

"I got on the treadmill this weekend and ran a few miles, and drinking plenty of water definitely helped my workout," he said.

Although he doesn't indulge often, Bell said giving up fizzy drinks for January is more of a personal test.

"I wouldn't say that I'm a big soda drinker, but I'm sure I could stand to reduce whatever I am drinking," he said. "If I have a meal, I [might] have a Coke or a ginger-ale or something like that."

His first test of the year was at last week's Duke basketball game. Tempted to grab a soda, he got lemonade instead.

NoFizz Charlotte is sponsoring the month-long challenge. The Charlotte-based group has grown from a Twitter feed to a nonprofit advocating the benefits of water. The group has signed up more than 6,000 people in 26 states and six countries for its monthly soda challenges, said Bobby DeMuro, executive director.

"It started as something as simple as drinking water, and I think it's taken a hold of people so much because it's so simple," he said.

As Americans struggle with obesity, over-consumption of soda continues to be a pervasive problem, DeMuro said.

"Soda is the number one source of calories in the American diet, and it's liquid calories so for a lot of people it's deceiving," he said. "If you're drinking two or three sodas a day on top of what you're eating, from that standpoint in over-consumption, soda is the number one issue."

But a short-term commitment can go far for long-term health.

"We have many people who take our challenge, [and] it's kind of a gateway," DeMuro said. "They start making these small changes and it's kind of ingrained in them before they know it."