Policy Forum
Jul 2004

The Physical Activity and Obesity Link: Considerations for Clinicians

John M. Jakicic, PhD
Virtual Mentor. 2004;6(7):327-329. doi: 10.1001/virtualmentor.2004.6.7.pfor2-0407.


Overweight and obesity are at epidemic levels among adults in the United States, with the prevalence rates increasing dramatically in children and adolescents.1,2 Physicians and other health care professionals are faced with the need to provide more treatment for an array of obesity-related conditions such as heart disease, diabetes, cancer, and musculoskeletal stress and strain. Therefore, it is more important than ever for physicians to focus on prevention.

Exercise for Controlling Chronic Illness

Modifications in eating habits and level of exercise can have a significant impact not only on overweight and obesity but on related chronic diseases. The importance of physical activity in chronic disease prevention and treatment is highlighted in the Surgeon General's Report on Physical Activity and Health, which concludes that physical activity reduces the onset of chronic conditions related to obesity such as cardiovascular disease, diabetes mellitus, and various forms of cancer.3 This reduction in morbidity may be a result of short- and long-term effects of physical activity on the body's regulation of lipids, blood glucose, insulin, and blood pressure. Health care professionals should consider incorporating physical activity into interventions for all these chronic conditions.

The recommended level of physical activity varies according to the desired health-related outcome for each patient. To reduce risk factors associated with morbidity and mortality of numerous chronic diseases, a patient should have at least 30 minutes of moderate-intensity physical activity (ie, similar to brisk walking) on most days of the week, or at least 150 minutes per week. This is consistent with the recommendations of the Centers for Disease Control and Prevention, the American College of Sports Medicine, and the Surgeon General's Report on Physical Activity and Health.3,4 Given the associated improvements in health, this should be the minimaltargeted level of physical activity recommended by physicians to their patients.

Exercise for Weight Control

To stem the tide of the obesity and overweight epidemics, health care professionals should also consider the level of physical activity necessary to control body weight. Current scientific data suggests that the level of physical activity necessary to maximize weight loss and minimize weight regain is greater than that required for other health-related outcomes. The American College of Sports Medicine, the Institute of Medicine, and the International Association for the Study of Obesity all recommend from 45 to 90 minutes per day of moderate-intensity physical activity for weight loss and control. Of course, this exercise regimen is most effective when combined with modifications in diet.5,6,7 This level of physical activity may pose a significant challenge for many patients who wish to control body weight; national surveys have indicated that approximately 25 to 30 percent of the adult population does not participate in any leisure-time physical activity.8

Physicians must find the right balance of increased physical activity and changes in eating behaviors for each patient. To do so, they should try to understand the barriers individual patients have to surmount to engage in physical activity.

Breaking Down Barriers to Physical Activity

Barriers to physical activity can be both individual and environmental. Environmental barriers include lack of adequate, affordable, and convenient recreation facilities within cities and communities, with the result that opportunities for sports participation and structured forms of exercise are limited or nonexistent. Environmental barriers also include absence of sidewalks and designated bicycle lanes and lack of traffic control. Safety concerns inhibit walking or jogging in some neighborhoods and communities. Because these environmental barriers limit forms of physical activity that were formerly part of daily activity (eg, walking to the grocery store, biking to school), they contribute to weight gain. Physicians should take an active role in encouraging creative planning of their neighborhoods and communities to ensure that there are opportunities for physical activity.

Of course, lack of participation in adequate levels of physical activity is not solely a result of environmental conditions. Helping patients break down the individual barriers may require an understanding of patient behavior that not all physicians currently have. As the importance of this role increases, physician training may begin to include greater exposure to the behavioral sciences so they can query patients about barriers and provide guidance to overcoming them. In the meantime, physicians can collaborate with behavioral specialists to design effective strategies for gaining patient compliance in the adoption and maintenance of adequate levels of exercise, diet control, and other health-related behaviors (eg, medication usage and preventive services).

At the community level, it is necessary to examine factors which have contributed to the obesity epidemic and to develop intervention strategies to reverse these trends. Here again, physicians and other health care professionals might work together in their neighborhoods and communities to improve physical activity opportunities.


  1. Flegal KM, Carroll MD, Ogden CL, Johnson CL. Prevalence and trends in obesity among US adults. JAMA. 2002;288(14):1723-1727.
  2. Ogden CL, Flegal KM, Carroll MD, Johnson CL. Prevalence and trends in overweight among US children and adolescents, 1999-2000. JAMA. 0200;288(14):1728-1732.
  3. US Department of Health and Human Services. Physical Activity and Health: A Report of the Surgeon General. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion; 1996.

  4. Pate RR, Pratt M, Blair SN, et al. Physical activity and public health: a recommendation from the Centers for Disease and Prevention and the American College of Sports Medicine. JAMA. 1995;273(5):402-407.
  5. Jakicic JM, Clark K, Coleman E, et al. American College of Sports Medicine Position Stand: Appropriate intervention strategies for weight loss and prevention of weight regain for adults. Med Sci Sports Exerc. 2001;33(12):2145-2156.
  6. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Protein and Amino Acids (Macronutrients): A Report of the Panel on Macronutrients, Subcommittees on Upper Reference Levels of Nutrients and Interpretation and Uses of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Washington, DC: The National Academies Press; 2002. Available at: http://books.nap.edu/books/0309085373/html/R1.html#pagetopAccessed June 29, 2004.

  7. Saris WHM, Blair SN, van Baak MA, et al. How much physical activity is enough to prevent unhealthy weight gain? Outcome of the IASO 1st Stock Conference and Consensus Statement. Obesity Reviews. 2003;4(2):101-114.
  8. Centers for Disease Control and Prevention. Prevalence of no leisure-time physical activity—35 states and the District of Columbia, 1988-2002. MMWR Morb Mortal Wkly Rep. 2004;53(4):82-86.


Virtual Mentor. 2004;6(7):327-329.



The viewpoints expressed in this article are those of the author(s) and do not necessarily reflect the views and policies of the AMA.