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Fitness vs. Fatness Debate

China Medical University, Lifu Teaching Building Taichung, Taiwan; April26 th 2011. Fitness vs. Fatness Debate. Eric.Ravussin@pbrc.edu. Obesity Facts. Over 66% of Americans are overweight or obese Number of Obese American adults rose to 33% Over last decade alone an increase of

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Fitness vs. Fatness Debate

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  1. China Medical University, Lifu Teaching Building Taichung, Taiwan; April26 th 2011 Fitness vs. Fatness Debate Eric.Ravussin@pbrc.edu

  2. Obesity Facts • Over 66% of Americans are overweight or obese • Number of Obese American adults rose to 33% • Over last decade alone an increase of • 12% - overweight • 70% - obese • Occurred for all population subsets: • children, elderly & all racial/ethnic groups • Second leading cause of preventable death • Over 280,000 – 325,000 obesity related deaths annually (including co-morbidities) Trust for America’s Health Facts 2005 http://www.cdc.gov/pcd/issues/2005/jan/04_0087.htm

  3. NHANES 1976-1980 NHANES 1999-2004 BMI distribution (%) Obese Overweight Extremely Obese Redman & Ravussin 2008

  4. Obesogenic Environment Environment Genetics 2 “Leptogenic” BMI (kg/m ) “Obesogenic” environment environment Traditional Environment Social Environment Built Environment 1900s 2000s Leptogenic Environment Obesity Susceptibility Obesity Susceptibility Genetics Obesity Resistant Obesity Prone Redman & Ravussin 2008

  5. Fitness vs. Fatness Debate • Obesity Epidemic: Reduced Physical Activity and/or Increased Energy Intake? • Fitness vs. Fatness Debate • Exercise for Weight Loss or Weight Maintenance?

  6. Estimates of Increased Energy Intake Since the 1970’s Hill JO et al Science 2003;299:853-855 Wang YC et al Pediatrics 2006;118:1721-1733

  7. Energy Intake 1910-2000 4000 3800 3600 3400 3200 3000 2800 2600 2400 2200 2000 Total Consumption – Uncorrected for waste Energy (kcal/d) Corrected for Waste 1900 1920 1940 1960 1980 2000 Year USDA/ERS Food Review 2002;25:2-15

  8. ‘Energy Imbalance Gap’ = the average difference between daily TEI (top line) and TEE (bottom line) needed to produce weight gain over a period of time ‘Energy Flux Gap’= the average difference in energy flux (TEI ≈ TEE) between two points in time Period of weight gain (Settling point A, lower mean weight) (Settling point B, higher mean weight) Energy Gap Terminology

  9. Some Assumptions and Consequences • Assumptions • En In = En Out = En Flux at ‘settling point’ • People are in virtual energy balance: “Energy Imbalance Gap” is very small • Consequences • “Energy Flux Gap” is large (US ~120kcal/day decade) • Population needs big changes to reverse to 1970s levels (~400kcal/day)

  10. Total EE in Adults • TEE, TEI and body weight are inter-related • Trend towards an equilibrium • Usual relationship is displayed with weight as the independent variable Swinburn, et al AJCN 2009 Jun;89:1723-8

  11. Energy Flux and Weight • Reverse the axes • Log the data • β=0.71 (not the reciprocal if axes reversed) • Use some algebra → a 10% difference in En Flux (En Intake) → 7% difference in weight (assuming age, gender, height constant) Swinburn, et al AJCN 2009 Jun;89:1723-8

  12. D• B • •A • C • E A=base case, B=↑EI, C=↓EI, D=↓PA, E=↑PA Swinburn, Sacks & Ravussin AJCN 2009

  13. ↓PA Mixture ↑EI Weight increase Is the epidemic due to ↑EI or ↓PA? • The equations could estimate the proportion of the epidemic due to ↓PA or ↑EI or mixture • NHANES changes in weight for adults and children • USDA calorie ‘disappearance’ data (proportioned for adults and children) Slope Adults 0.71 Children 0.43 Swinburn, Sacks & Ravussin AJCN 2009

  14. ‘Measured’ vs. Predicted Changes Swinburn, Sacks & Ravussin AJCN 2009 Weight from NHANES, EnFlux from USDA Weight predicted from equations at USDA EnFlux

  15. Summary and Issues • Terminology and values for the ‘energy gaps’ • Increased energy intake has been the major drive of the epidemic • Stopping the epidemic • Returning to 1970s level • Need behavioural interventions and environmental interventions • Distinguish the drivers (EI) vs. the modulators (physiology, genetics...)

  16. Fitness vs. Fatness Debate • Obesity Epidemic: Reduced Physical Activity and/or Increased Energy Intake? • Fitness vs. Fatness Debate • Exercise for Weight Loss or Weight Maintenance?

  17. Risk of Developing Diabetes & BMI:Nurses Health Study (n= 68,907) BMI Rana et al Diab Care Jan 2007

  18. Aerobics Center Longitudinal Study Database • Dr. Steve Blair & Dr Tim Church • Consists of Cooper Clinic patients • >70,000 individuals enrolled • Examinations dating back to 1970 • Follow-up for mortality and morbidity • every 3-4 years

  19. Fitness Testing • Maximal exercise test on a treadmill (Balke) • Standardized fitness categories based on age, gender & time on treadmill: • Fitness => measure of physical activity habits

  20. Fitness Classifications • Low Fitness = “Unfit” • Lower 20% time on treadmill for gender and age • Moderate Fitness- • Next 40% time on treadmill for gender and age • @150 minutes of walking per week • High Fitness- • Highest 40% time on treadmill for gender and age

  21. Diabetes Incidence Rates By Fitness Groups, Men (n=8633) Diabetes incidence/1000 men Cardiorespiratory Fitness Groups Wei M et al. Ann Int Med 1999

  22. Diabetes Incidence Rates by Fitness: ACLS (n =13,190) P trend < 0.0001 Maximal METs unpublished

  23. Risk of Diabetes By Physical Activity-Fatness - NHS Rana et al Diab Care Jan 2007

  24. Risk of Diabetes By Physical Activity-Fatness - NHS Supported by Numerous Other Studies Rana et al Diab Care Jan 2007

  25. CVD Mortality by Fitness Men with Diabetes Church et al, Arch Int Med, 2005

  26. Fitness & Risk CVD in Individuals with Diabetes Church et al, Arch Int Med, 2005

  27. Fit-Fat & Risk CVD in Individuals with Diabetes Church et al, Archives of Internal Medicine, 2005

  28. CVD Mortality Risk by Fitness-Fatness: Men with DM Church et al, Archives of Internal Medicine, 2005

  29. CVD Mortality Risk by Fitness-Fatness: Men with DM Fitness Church et al, Archives of Internal Medicine, 2005

  30. Fitness Weight Weight DM CVD Fitness

  31. Fitness Weight Weight X DM CVD Fitness

  32. Summary • Obesity increases risk of diabetes • Independent of physical activity • Appears to be more important than PA • Obesity increases risk of CVD • Negated when fitness is accounted for

  33. How does fitness protect overweight/obese individuals with diabetes from CVD?

  34. Exercise is Pleiotropic

  35. Diabetes Incidence Rates by Fitness: ACLS (n =13,190) Why ? P trend < 0.0001 Maximal METs

  36. Expected Relation Expected Relation

  37. Expected Relation

  38. Fitness vs. Fatness Debate • Obesity Epidemic: Reduced Physical Activity and/or Increased Energy Intake? • Fitness vs. Fatness debate • Exercise for Weight Loss or Weight Maintenance?

  39. 30 minutes

  40. Prevalence of people in each state meeting current public health physical activity recommendationsUS Centers for Disease Control and Prevention (2005) 5 days a week for 30 min/d moderate intensity activity or at least 3 days a week for 20 min/d of vigorous intensity activity or the equivalent of 1,000 kcal/wk in activity

  41. Exercise-Induced Weight Loss Reduction in Obesity and Related Comorbid Conditions after Diet-Induced Weight Loss or Exercise-Induced Weight Loss in Men (N=52; 3 mo; 700kcal/d) (R Ross et al Ann Int Med 2000; 92-103) Exercise-Induced Redduction in Obesity and Insulin Resistance in Women: a RCT (N=54; 14-wk; 500Kcal/d) (R Ross et al; Obes Res 2004; 789-98) Effect of a 16-m Randomized Controlled Exercise Trial on Body Weight and Composition in Young Overweight Men and Women (N=74; 16 mo; 400 kcal/d for 5 days) (JE Donnelly et al; Ann Int Med 2003; 1343-50) Effect of Calorie Restriction with or without Exercise on Body Composition and Fat Distribution (LM Redman et al; JCEM 2007; 875-82)

  42. Healthy Diet Control (n=12) 25% CR (n=12) Baseline (n=36) Randomization 12.5% CR + 12.5% EX (n=12) Food Provided Food at Home FP Weeks -5 -3 0 12 24 Body composition – DXA Abdominal Fat – Multi slice CT Aerobic Capacity – VO2peak (treadmill) Fasting lipids Insulin Sensitivity – MinMod (Bergman) Study Overview

  43. CR CR+EX Control 100 Energy Deficit Energy Deficit 75 Healthy Diet Dietary Restriction Aerobic Exercise Dietary Restriction only Daily Energy Requirement + Caloric Prescription Energy Requirement for weight maintenance 2 x 14d Doubly Labeled Water

  44. Body Mass Change * ~ 10% No difference between CR and CR+EX * Significant change from baseline

  45. Body Fat Change Fat Mass by DXA Visceral Fat by CT * * * * No difference between CR and CR+EX * Significant change from baseline

  46. National Weight Control Registry(av. Wt loss 30kg for 5 years) Eat a diet low in fat Self monitoring of weight and food intake Very high level of physical activity

  47. Physical Activity Recommendations (CDC) Current physical activity recommendations call for 30 minutes of moderate intensity activity on most days of the week, or the equivalent of expending approximately 1,000 kcal in activity per week The Role of Physical Activity in Maintaining a Reduced Weight (Johannsen DL & Ravussin, Curr Athero Rep 2007)

  48. Reduction in chronic disease and all-cause mortality with current recommendations of 30 min per day (1000 Kcal/wk) 60-90 min/d of moderate activity is necessary to maintain a reduced weight (2600-2800 Kcal/wk) Energy Expenditure in Physical Activity for Maintenance of Weight Loss

  49. The challenge is not living longer…… The new challenge is living better longer

  50. Dr Cefalu is on his way for a long healthy life but …. It is hard work

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