Slide 1Unrealistic Weight Loss GoalsThe problem of compensation!Slide 4Energy Metabolism Before and After Weight LossEffects of Food Restriction/DietSlide 7Slide 8Why is weight loss so difficult? compensation!Three Important FactsSlide 11Slide 12Lee, et al. 1999 ACLSAll Cause MortalityMetabolically healthy but obeseSlide 16National weight control registry (NWCR)To examine physical activity levels of NWCR participantsSlide 19Predictors of weight maintenancePredictors of weight maintenanceObesity Lecture 41) Why is weight loss so difficult?2)Is healthy obesity possible?3) What makes people successful at losing weight?Unrealistic Weight Loss GoalsOutcome Weight (lbs)% ReductionInitial 218 0Dream 135 38Happy 150 31Acceptable 163 25Disappointed180 17Foster et al. J Consult Clin Psychol 1997;65:79.The problem of compensation!•Compensation with reduced intake (diet)–TEE–RMR–TEF•Compensation with increased expenditure–Reduced EE with exercise–Satiety/HungerREMEMBER: Do changes in weight influence 24-hour energy expenditure?Diet-induced weight loss causes a decrease in EE!Measured via indirect calorimetry and doubly labeled waterLeibel, et al 19950500100015002000250030003500Energy Metabolism Before and After Weight LossEnergy Expenditure (kcal/d)Before*P<0.05 vs before weight lossAmatruda et al. J. Clin Invest 1993;92:1236.PredictedMean BMI Reduced from 31 to 23 kg/m2After Before PredictedAfterResting Energy Expenditure (RMR)Total Energy Expenditure****Effects of Food Restriction/DietResting metabolic rate Thermic effect of food Thermic effect of activity/energy expenditure due to physical activity Total daily energy expenditure Can exercise training attenuate the decrease in RMR and TEE that is seen with diet?With adding exercise, PA EE should increase, right???Some evidence shows when people increase exercise, they decrease spontaneous PA!–unstructured activity of daily living (NEAT)If body mass decreases, with training, fitness improves, and person is more efficient ( work output/ EE), EE of any exercise decreases with weight loss–work harder for same effectRole of AppetiteREMEMBER: Deviation from Prescribed Diet in Kcals per Week (women), Wadden, et al.Condition Week 5 Week 17Diet Alone 206 817Aerobic 455 1,041Strength 481 1,153Combined 243 1,172Why is weight loss so difficult?compensation!1) Reductions in weight cause changes in energy metabolism that make energy expenditure more difficult2) Exercise may cause changes in spontaneous physical activity3) Reductions in weight lead to lower energy expenditure with exercise. 4) Exercise may cause changes in intakeThree Important Facts1 pound of fat = kcals1 mile walk/jog/run = 100 kcalsWeight change (+ or -) = Energy intake – Energy expenditureRealistic Expectations Based Just on Exercise Energy ExpenditureWalk 3 miles/day, 6 days/wk in weight loss program while also decreasing caloric intake100 kcal * 3* 6 =1800 kcal/wk caloric expenditure = 0.5 lbs/wk weight loss1800/3500 = .5If RMR  by 100 kcal/day, weight loss  to 0.33 lbs/wk1800-700kcal = 11001100/3500 ~ 0 .3If RMR  by 200 kcal/day, weight loss  to 0.1 lbs/wk1800-1400 = 400400/3500 ~ 0.11800-1700 = 1100110/3500= .31800-1400= 400400/3500= .1Exercise vs. gastric bypass: 570 – 350lbs!Is healthy obesity possible?“Fit but Fat”Lee, et al. 1999 ACLSHigher adiposity = greater CVD mortality BUT CRF attenuated this associationUnfitFitAll Cause MortalityMetabolically healthy but obeseOrtega, et al. 2012ACLS Data McAuley, et al. 2012National weight control registry (NWCR)•Established in 1993•What determines successful weight loss maintenance?•10,000 participants–Largest longitudinal prospective study of successful weight loss–Maintain at least 30 lb (13.6kg) weight loss for at least 1 yrTo examine physical activity levels of NWCR participants•887 males and 2800 females•Enrolled in registry between 1993 and 1996•Maintained weight loss of 30lb for 1 yr•No weight loss surgery• PA was asses using the Paffenbarger PA questioinnaire•2011 – follow up with objectively measures MVPA Catenacci et al., Obesity, 2008Catenacci et al., Obesity, 2008Predictors of weight maintenance1) engaging in high levels of physical activity2011 follow up showed weight maintainers spent more time/day MVPA – 60/90 min/day is recommended for formerly obese people to maintain weight loss 2) eating a diet that is low in calories and fat 3) eating breakfast 4) maintaining a consistent eating patternWing et al, 2005Predictors of weight maintenance4) self-monitoring weight on a regular basis5) catching "slips" before they turn into larger regains6) TV viewing < 10 hrs/weekWing et al,