Adults need at least 250 minutes per week -- equal to 50 minutes of exercise five days a week -- to lose significant weight, according to the latest recommendations from the American College of Sports Medicine (ACSM).

“In the midst of a genuine crisis in Americans' health related to what we eat and how little we move, these guidelines are meant to provide an understanding and clarification of the role of physical activity and its relationship to weight,” Joseph E. Donnelly, chairman of the writing committee, says in a written statement. “Now that we have the latest information on how much physical activity is part of the equation, we can continue the educational process to help people who struggle with their weight.”

If you are trying to maintain your weight rather than lose, you may still be OK with the 30-minute workouts. The ACSM recommends that adults participate in at least 150 minutes per week of moderate-intensity physical activity to prevent significant weight gain. Overweight and obese adults, however, are more likely to reach their goals with at least 250 minutes. The report also recommends strength training as part of the exercise regimen, in order to increase fat-free mass and further reduce health risks.

The recommendations are published in Medicine & Science in Sports & Exercise. They are in line with the recent recommendations published by the U.S. Department of Health and Human Services.

Weight management is an important public health issue, the report says. More than 66% of U.S. adults are either overweight or obese. People can reduce their risk for chronic diseases with as little as a 2% to 3% reduction in excess body weight.