As many as 40% of women and 24% of men are trying to lose weight at any given time.<sup>70 National Institutes of Health Conference Panel Methods for voluntary weight loss and control Ann Intern Med 1993 ;  119 : 764

Cliquez ici pour aller à la section Références</sup> Exercise has been used as a unique mode of treatment for obesity. Most often, it has been included as part of weight-reducing programs which include dietary restriction and behavior modification. Because a large number of people are overweight, and because that number is growing,<sup>53 Kucznarski R., Flegal K., Campbell S. , et al. Increasing prevalence of overweight among US adults: The national health and nutrition examination surveys, 1960–1991 JAMA 1994 ;  272 : 205

Cliquez ici pour aller à la section Références</sup> there is an absolute need to develop effective treatment or preventive approaches for obesity so that the negative health consequences associated with this condition can be eliminated. This article reviews the efficacy of using exercise as a practical treatment for obesity.

Obesity can be defined as the excessive accumulation of body fat. In the literature, frequent reference is made to moderate and severe obesity. In this article, moderate obesity is defined as a body mass index (BMI), calculated as weight in kilograms divided by height in meters squared, of between 27 and 31 and severe obesity as a BMI of greater than 31. Similar criteria were used by Atkinson and Walberg-Rankin<sup>6 Atkinson R., Walberg-Rankin J. Physical activity, fitness, and severe obesity Physical Activity Fitness and Health. International Proceedings and Consensus Statement Champaign, IL: Human Kinetics Publishers (1994).  696

Cliquez ici pour aller à la section Références</sup> in their recent review. Exercise or physical activity is defined as any rhythmical activity which elevates heart rate above resting levels and involves the use of a large muscle group or the coordinated use of several large muscle groups. Examples of such exercise include walking/jogging, cycling, aerobic dance, rowing, stair climbing, skating (ice, roller, and roller blade), and weight lifting. Participation in sport activities such as volleyball, basketball, softball, and soccer is also defined as exercise. The overall hypothesis is that regular exercise elevates total daily energy expenditure (TDEE) and that as long as this increase in energy expenditure is not offset by an increase in energy intake, weight loss or weight maintenance following a period of weight loss will be achieved.

Reasons for the recent surge in the prevalence of obesity are not completely understood. The increased incidence is most likely not the result of a shift in the genetic milieu of most affluent societies making them more susceptible to becoming overfat but rather a reflection of how the current environment interacts with a genetic background. Lifestyles have changed in recent years such that physical activity is reduced, food is abundant and readily available, consumption of fruits and vegetables is decreased, and sugar and fat intake is increased. Most likely, these changes in habitual daily living have resulted in an increasing number of overweight individuals. Much of the literature reviewed in this paper describes the effects of a formal exercise program on reversal or prevention of obesity. Physical activity is no longer a part of our daily routines, and, as such, we are forced to find time to implement a formal program of exercise. This makes exercise a chore, less interesting, and therefore more likely to be cut out of our daily routines. This poses an intriguing question: in our current lifestyle, do we need formal exercise programs or do we need to be less inactive?