Exercise Really Is Key to Weight Loss and Maintenance

A couple of years ago we reported on a study that showed the importance of exercise in achieving and maintaining weight loss (11/03/06). At a minimum, the National Institute of Health and the Center for Disease Control recommend thirty minutes per day of exercise on most days of the week, or 150 minutes per week. Studies also show, however, that the difficulty is not really in losing the weight - it's in keeping it off for the long term. How much exercise is necessary to help maintain weight loss?

Researchers at the University of Pittsburgh, Brown Medical School, and Wake Forest University recruited 170 overweight or obese women who had signed up with a hospital-based weight loss research center (Arch Intern Med 2008;168(14):1550-1559). These women were all between 21 and 45, were otherwise healthy, and exercised less than three days per week for twenty minutes or less at a time.

Those women who began the two-year study weighing less than 90kg (about 200 lbs.) were prescribed a 1200 calorie per day diet, while those who weighed more than 200 lbs. were prescribed a 1500 calorie per day diet. All of the women were randomly assigned to one of four exercise programs:

• Moderate intensity/moderate calorie-burning;
• Moderate intensity/high calorie-burning;
• Vigorous intensity/moderate calorie-burning; and
• Vigorous intensity/high calorie-burning

The high calorie-burning groups were to burn about 2000 calories per week, while the moderate calorie-burning groups were to burn about 1000 calories per week. The participants used their heart rate and their own perception of exertion to define whether an exercise was moderate or high intensity.

All of the women lost weight in the first six months, then gained some weight back every six months. After the 24 months of the study, however, those women who exercised vigorously and burned over 2000 calories per week (the high intensity/high calorie-burning group) lost the most initially and regained the least. At the six-month mark, those women had lost 9.5kg (about 21 pounds). At the 24-month mark, they'd maintained the loss of 5.8kg (about 13 pounds) - they'd only gained back 3.7kg (about 8 pounds).

By comparison, those women assigned to the moderate intensity and moderate calorie-burning group lost 8.2kg (18 pounds) and kept off 4.7kg (slightly over 10 pounds). They'd gained back 3.5kg (8 pounds).

When the scientists interviewed those few women who actually maintained their loss of 10% of their body weight, they found that these women had actually performed an average of 68 minutes of exercise per day, five days per week. That's over twice as much as the CDC recommends for maintaining weight loss!

What this means for you

Exercise, exercise, exercise. Make your health a priority in your life by making exercise a priority. Schedule that time - don't just do it “when I have a minute.” If you have kids, make exercise a family affair by walking or bicycling together - or at the same time. One mother we know takes her kids to soccer in the afternoons and uses that time to walk around the high school's track. Whatever you do, do something you like and do it consistently.

First posted: October 1, 2008