Weight Is Easier Gained Than Lost When Exercise Is Inconsistent

Weight gain caused by inconsistent exercise cannot be lost by simply resuming a previous exercise routine, suggests a study published in the February 2008 issue Medicine & Science in Sports & Exercise®, the official scientific journal of the American College of Sports Medicine (ACSM).

In an eight-year study of more than 40,000 runners, researcher Paul Williams, Ph.D., found that weight gain among men and women who decreased their running distances per week was significantly more than weight loss among men and women who increased their running distances per week by the same amount.

"If you stop exercising with the intention of starting again later, you don't get to pick up where you left off," Thompson said. "You're likely to gain weight and get stuck with it unless you exercise a lot more. It's an ounce of prevention or a pound of cure, literally."

Additionally, substantial weight loss in participants did not occur unless running distances were more than 25 kilometers (15.5 miles) per week for men, and 48 kilometers (29.8 miles) per week for women. Participants who already ran a long distance per week and decreased their running, still maintaining a long distance per week, gained significantly less weight than those whose running distances started shorter and decreased to even less.

"We saw the most weight gain in subjects who were approaching a very sedentary lifestyle," Williams said. "This concurs with the vast amount of research showing that at least some daily activity is necessary to prevent significant weight gain."

Williams believes that exercise has taken a back seat to controlling diet in addressing America's obesity epidemic. The key, he says, is to start exercising before weight gain actually occurs.

ACSM and the American Heart Association recommend that healthy adults engage in physical activity for at least 30 minutes, five days per week, at a moderate intensity, or 20 minutes, three days per week, at a vigorous intensity. Individuals striving for weight loss may need to exercise as many as 60 to 90 minutes per day.

"Although this study showed weight loss when running at high levels, others may want to do a different type of activity," Williams said. "Whether it's running, cycling, swimming, or something else, the important thing to remember is that activity is needed for a healthy lifestyle that prevents weight gain."

Medicine & Science in Sports & Exercise® is the official journal of the American College of Sports Medicine, and is available from Lippincott Williams & Wilkins at 1-800-638-6423.