Regular gym-goers know it isn’t easy to find an unoccupied treadmill right after New Year’s Day, with the rush of people who turn to exercise to lose holiday pounds and fight winter boredom.

If you've also made a commitment to get fit in 2016, then feel free to sign up for an eight-week bootcamp fitness class or log miles on the treadmill to improve your overall health. But don’t get too disappointed if the weight doesn't come off after all those hard sweat sessions.

The latest research suggests that you likely won’t lose weight from exercise alone without adopting healthy eating habits as well, says D.C. (Duck-chul) Lee, an assistant professor at the Department of Kinesiology at Iowa State University.

“The problem is their passion. Especially in early January, everybody wants to exercise and buy a gym membership, and they are...