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 Men Women *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, 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 Rönnemaa 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) MenWomen * 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) Diet Only Diet + Exercise * 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) WeeklyBiweeklyMonthly 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) Jeffery et al. Am J Clin Nutr 2003;78: 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 Home-basedGroup-based * * * * * *

Effect of Group-Based vs Home-Based Physical Activity on Body Weight Weight Change (kg) Time (months) 0369 Perri et al. J Consult Clin Psychol 1997;65: Group-based Home-based *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 Weight Loss (kg) P=0.08P=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: 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:

Decreasing Television Viewing Leads to improved Body Mass Index in Children 6-month intervention Robinson JAMA 1999;282:1561. Control Change in BMI (kg/m 2 ) 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