Researchers at UAB have found that combining a calorie-restricted diet with high-intensity interval training could be a solution for reducing weight regain after weight loss.

"One of the problems when you restrict calories on a diet is that you lose muscle mass, and as a result, your metabolism slows down to accommodate the restriction of food," said Eric Plaisance, PhD, assistant professor of exercise science in the UAB School of Education. "80 percent of people who lose weight by dieting gain all of it back in a four- to five-year period."

Moderate-intensity exercise, such as a brisk walk or dancing, has been shown to reduce the lowering of one's metabolic rate while restricting calories. In a study published in the American Journal of Physiology, the UAB research team found that in the presence of a calorie-restricted diet, high-intensity exercise training preserved muscle mass and had a greater impact on the way the body uses glucose for energy in mice.

High-intensity interval training is a process in which a person performs near maximal exercise for a short period of time, and then performs two to four minutes of active recovery; for example, if someone is on a treadmill they may go from running to walking. Then the person performs another cycle of near maximal exercise and active recovery and continues to do so for four to five cycles.

Plaisance says previous research shows that continuous moderate intensity exercise does burn more calories, but further studies have shown that people who perform high-intensity interval training seem to produce the same amount of weight loss doing 20 minutes of exercise as those who do 60 minutes of moderate-intensity exercise.

"Most people tell us they do not exercise for lack of time," Plaisance said. "High-intensity interval training takes about a third of the time as a continuous exercise training."