While exercise alone as a weight-loss method is of limited value, its role in preventing initial weight gain and
preventing regain of weight that has been lost is well established.
Many studies have suggested that the amount of exercise needed to prevent initial weight gain and the level of exercise needed to sustain a weight loss are different. In addition, the amount of exercise required for weight management appears to be greater than the amount needed to achieve general health benefits.
Recommended Levels of Activity
The current recommendation for physical activity encourages adults to do 30 minutes of moderate intensity activity on most days, and preferably all days, of the week. The majority of people currently don't achieve this goal, which is considered a reasonable and obtainable one that would benefit most people. This level of activity has been linked with limiting the health risks for a number of chronic diseases including coronary heart disease and diabetes.
As part of a consensus statement published by the International Association for the Study of Obesity (IASO), the recommendation of
45-60 minutes of moderate intensity activity each day was made to prevent the development of
overweight or obesity. The IASO report goes on to recommend obtaining this activity by reducing sedentary behavior and focusing on including lifestyle activities (such as gardening, brisk walking, and household chores) and leisure-time activities into the daily routine.
A more recent, randomized controlled study found that 30 minutes of moderate intensity activity (the equivalent of walking 12 miles per week) was sufficient to prevent weight gain.
Exercise & Sustained Weight Loss
Regular physical activity is one of the best predictors of weight-loss maintenance. In addition, the amount of exercise connected with sustained weight loss is consistent from study to study,
and it is a significant amount.
People in the National Weight Control Registry, a database of people who have lost at least 30 pounds and kept if off for at least one year, report expending over 2,800 calories per week doing physical activity. These people also report that they find activity an enjoyable part of their lives and look at this weight maintaining as a pleasure, not a chore.
Another study found that 1,500-2,000 calories per week of exercise (equivalent to walking 15-20 miles) is associated with improved weight maintenance. http://www.weightwatchers.com/templa...Date=5/15/2008