The Role of Physical Activity in Obesity Therapy
Benefits of Regular Physical Activity in Obese Persons
Decreases loss of fat-free mass associated with weight loss
Improves maintenance of weight loss
Improves cardiovascular and metabolic health, independent of weight loss
Physical Activity Helps Preserve Fat-Free Mass During Weight Loss
Diet Only
Loss of Fat-Free Mass (% Total Weight Loss)
Ballor and Poehlman. Int J Obes Relat Metab Disord 1994;18:35.
Diet Plus Physical Activity
*P<0.05
Energy Expenditure of Physical Activity
Energy Expenditure (kcal/h)
Adapted from: Alpers. Undergraduate Teaching Project. Nutrition: energy and protein. American Gastroenterological Association, 1978.
All out competitive sports
Running 10 mph
Running 6 mph
Climbing stairs
Sexual intercourse
Gardening
Walking 4 mph
Bicycling
Walking 2 mph
Chewing gum (11 kcal/h)
Physical Activity Alone Results in Minimal Weight Loss
Wing. Med Sci Sports Exerc 1999;31(suppl):S547.
*P<0.05 vs control group
Duration of each study ranged from 4 to 12 months.
Stefanick 1998
Stefanick 1998a
Anderssen 1995
Hammer 1989
Verity 1989
R?nnemaa 1988
Wood 1988
Wood 1983
Weight loss (kg)
Control Group
Exercise Group
*
*
*
*
Effect of 16-month Supervised Aerobic Exercise on Body Weight in Overweight and Obese Young Adults
Donnelly et al.Arch Intern Med 2003;163:1343
*p<0.05 vs control
Weight Change (kg)
Men
Women
*
Control
Exercise
*
Physical Activity Usually Does Not Increase Short-Term Diet-Induced Weight Loss
*P<0.05 vs diet-only group.
Wadden 1997
Ross 1996
Marks 1995
Ross 1995
Blonk 1994
Sweeney 1993
Bertram 1990
Weight loss (kg)
*
Wing RR. Med Sci Sports Exerc. 1999;31(suppl):S547-S552.
Each study ranged from 4 to 6 months.
Relationship Between Physical Activity and Maintenance of Weight Loss
Not Maintained
Subjects Exercising (%)
P<0.001
Kayman et al. Am J Clin Nutr 1990;52:800.
Weight Loss Pattern
Maintained
Considerable Physical Activity is Necessary for Weight Loss Maintenance
Jakicic et al. JAMA 1999;282:1554.
Change in Weight (kg)
Time (months)
0
6
12
18
Weekly
Biweekly
Monthly
Concomitant Behavior Therapy
*P<0.05
<150 min/wk
>150 min/wk
>200 min/wk
Effect of Low-Activity (1000 kcal/wk) and High-Activity (2500 kcal/wk) on Body Weight
0
Months
Weight Change (kg)
6
12
18
Jeffery et al. Am J Clin Nutr 2003;78:684-689.
P < 0.05
Behavior therapy + Low activity
Behavior therapy + High activity
Compliance is Greater with Home-Based versus Group-Based Activity
1
Sessions Completed (%)
Perri et al. J Consult Clin Psychol 1997;65:278.
* P<0.05 group-based vs home-based.
Month
2
3
4
5
6
7
8
9
10
11
12
Home-based
Group-based
*
*
*
*
*
*
Effect of Group-Based vs Home-Based Physical Activity on Body Weight
Weight Change (kg)
Time (months)
0
3
6
9
Perri et al. J Consult Clin Psychol 1997;65:278.
12
15
*P<0.05
Effect of Long vs Short Bouts of Exercise on Total Amount of Activity and Weight Loss
Long bout = one 40-min session. Short bout = four 10-min sessions.
Activity (min/wk)
Long Bouts
Short Bouts
Long Bouts
Short Bouts
P=0.08
P=0.07
Jakicic et al. J Obes Relat Metab Disord 1995;19:893.
Weight Maintenance Can Be Achieved with Either Programmed or Lifestyle Activity
Weight Change (kg)
Time (months)
Diet + programmed activity
Diet + lifestyle activity
P=0.06
Andersen et al. JAMA 1999;281:335.
Treatment Phase
Maintenance Phase
Effect of Decreasing Sedentary Activities vs Increasing Physical Activities on Body Weight in Children 6-12 Years Old
0
Time (months)
Decreased Sedentary Activity
Change in Percent Overweight
Increased Physical Activity
Epstein et al. Health Psychol 1995;14:109.
4
8
12
Decreasing Television Viewing Leads to improved Body Mass Index in Children
6-month intervention
Robinson JAMA 1999;282:1561.
Control
Change in BMI (kg/m2)
6-month intervention
Control
Change in TV viewing (h/wk)
P=0.002
P<0.001
Fatness, Fitness and Cardiovascular Disease Mortality
Lean <16.7%
Relative Risk of CVD Mortality
Body Fat Category (% Weight as Fat)
Lee et al. Am J Clin Nutr 1999;69:373.
Normal 16.7%-24.9%
Obese >25%
Aerobically fit
Unfit
Guidelines for Increasing Physical Activity
Assessment
1) Medical and psychological readiness
2) Physical limitations
3) Current activities
4) Barriers to activity
Develop physical activity plan
Start activity slowly and gradually increase planned aerobic activity to 200 min/wk
Enhance compliance
Programmed vs lifestyle activity
At-home vs onsite activity
Multiple short bouts vs single long bout of activity