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Challenges to tacking the obesity epidemic: Why public health approaches do not work

Challenges to tacking the obesity epidemic: Why public health approaches do not work. Joe Proietto University of Melbourne Department of Medicine Repatriation Hospital Austin Health Heidelberg Victoria. THE EPIDEMIC. Prevalence. Cameron AJ et al MJA 178: 427-432 2003. The Scourge.

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Challenges to tacking the obesity epidemic: Why public health approaches do not work

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  1. Challenges to tacking the obesity epidemic: Why public health approaches do not work Joe Proietto University of Melbourne Department of Medicine Repatriation Hospital Austin Health Heidelberg Victoria

  2. THE EPIDEMIC

  3. Prevalence Cameron AJ et al MJA 178: 427-432 2003

  4. The Scourge 2. NHMRC 2003

  5. How Should we tackle the Obesity Epidemic?

  6. “Common sense” tells us that obesity is caused by eating too much and not exercising enough. If so, the solution is clear and easy. To stem the obesity epidemic, we must simply educate the public about their eating and lifestyle behaviours.

  7. From the “NorthEast & Region” Wednesday March 10 2004

  8. The Minnesota Heart Health Program • A 13 year research and demonstration program • Included 3 demonstration communities and 3 matched control communities • Primary end-point was reduction in cardiovascular risk achieved mainly by lifestyle modification leading to weight loss.

  9. The Minnesota Heart Health Program • Mass media campaigns were conducted for the duration of the program • These media campaigns educated the people on: * the link between obesity and cardiovascular risk • * behaviours that could contribute to the development of obesity • * Services available to assist them with weight loss

  10. Impact of education on body weight Cohort Study Jeffery RW et al. Int J Obes Relat Metab Disord 19:30-39 1995

  11. Why did the public health measures in the Minnesota Heart Health Program fail to influence the weight gain? The Authors concluded that there were too many “negative” messages and that these overwhelmed the healthy messages.

  12. What negative messages do we have? Australian children watch an average of 2.5 hours of television per day. Advertisements can occur at the rate of 30 per hour Food ads, as a percentage of total ads on television, range from 25%-48% (average 34%). (Hill and Radimer, 1997). Young Media Australia

  13. A junk food advertising audit conducted by the Australian Divisions of General Practice National Divisions Youth Alliance in January 2003 analysed 50 hours of child targeted TV on commercial stations. Dr Andrew Binns Medicine Australia

  14. Children watching two and a half hours of TV a day during the holiday period would have been exposed to 406 advertising messages encouraging them to eat junk food. Dr Andrew Binns Medicine Australia

  15. What do you think the chances are of reducing this exposure to negative messages ?

  16. The Age 28 July 2006

  17. Controlling food intake Can we reduce the exposure to negative messages? Probably over time Can we reduce the exposure of the population to energy dense food available in abundance all year round? Probably not

  18. Physical activity

  19. The World Today - Tuesday, 29 June, 2004  12:30:00 PM promises to spend on childhood obesity solutions Reporter: Alexandra Kirk The Prime Minister has promised to spend $116 million to tackle the problem of childhood obesity. Mr Howard said the plan was built on "common sense", as he called for support from the whole community to get children moving and eating well. Mr Howard has already rejected Labor's plan to ban fast food advertising during children's television programs, saying that would take responsibility away from parents.

  20. The Age 9 May 2007

  21. Contribution of timetabled physical education to total physical activity in primary school children: cross sectional study Katie M Mallam,et al. BMJ 327:592-593 2003 Monitored physical activity during waking hours for 7 days using accelerometers in 3 schools. Studied 120 boys and 95 girls aged 7.5-10.5 years.

  22. School 1 was wealthy with extensive facilities and 9.0 a week timetabled physical activity. School 2 was and award winning village school with 2.2 hours per week of timetabled physical education sessions. School 3 was an inner city school with limited or no sporting facilities and 1.8 hours timetabled physical education per week.

  23. Katie M Mallam,et al BMJ 327:592-593 2003

  24. Conclusion “The total amount of physical activity done by primary school children does not depend on how much physical education is timetabled at school because children compensate out of school.” Katie M Mallam,et al BMJ 327:592-593 2003

  25. Moodie ML, Carter RC, Swinburn BA, Haby MM. The cost-effectiveness of Australia's Active After-School Communities program. Obesity (Silver Spring). 2010 Aug;18(8):1585-92. Epub 2009 Nov 5. “For 1 year, the intervention cost is Australian dollars (AUD) 40.3 million (95% uncertainty interval AUD 28.6 million; AUD 56.2 million), and resulted in an incremental saving of 450 (250; 770) DALYs. The resultant cost-offsets were AUD 3.7 million, producing a net cost per DALY saved of AUD 82,000 (95% uncertainty interval AUD 40,000; AUD 165,000). Although the program has intuitive appeal, it was not cost-effective under base-case modeling assumptions.”

  26. Reduced Physical Activity: 3 types of activity Past Now (5,000,000 BC -1800) (1800-2010) a) Obligatory + + + +- b) Voluntary + + c) Spontaneous + +

  27. CHOICE

  28. Can we engineer society to force increased physical activity? Probably not

  29. Summary There are significant political, social, economic and cultural impediments to stemming the obesity epidemic.

  30. Biological impediments to limiting the obesity epidemic

  31. NH&MRC 2003

  32. Long term effects of weight loss – diet therapy

  33. Long term effects of weight loss – Physical activity

  34. Long term effects of weight loss – Behaviour therapy

  35. Long term effects of weight loss –Surgery

  36. WHY THESE RESULTS? Why is it that for most, the only therapy that works long term is the one that removes choice?

  37. Weight is Homeostatically Regulated

  38. Paraventricular Hypothalamic Nucleus Oxytocin CRH Brain Stem Lateral Hypothalamus Orexin MCH Arcuate Nucleus NPY CART AGRP aMSH Cerebral Cortex conscious will Opioids Dopamine Endocannabinoids - + - Ghrelin CCK PYY3-36 GLP-1 Oxyntomodulin Insulin Amylin PP Leptin FOOD INTAKE ENERGY EXPENDITURE

  39. The consequence of the homeostatic regulation of body weight is that after weight loss, the body puts in place mechanisms to drive weight regain.What are these mechanisms?

  40. Changes in Leptin levels with dieting Geldszus et al. Eur J Endocrinol 1996; 135: 659-62

  41. 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 p=0.016 30 CCK AUC (pmol/L/4h) 20 Plasma CCK (pmol/L) 10 Week 0 0 Week 9 0 60 120 180 240 Time (min) Post- breakfast CCK release pre and post weight loss Chearskul S. et al. American Journal of Clinical Nutrition, 87: 1238-1246, May 2008

  42. Ghrelin levels after weight loss 8. Cummings 2002

  43. What determines the weight that the homeostatic mechanisms try to defend?

  44. Weight is Genetically Determined

  45. Genes and Obesity

  46. BMI- Intrapair Correlations Stunkard AJ et al New Engl J Med 322:1483-7 1990

  47. Effect of 100 days of overfeeding in 12 pairs of identical twins Twin A Abdominal Fat gain Twin B Abdominal Fat gain Bouchard C et al New Engl J Med 322:1477-82 1990

  48. So Obesity is genetic…… BUT……

  49. Prevalence (cont) Cameron AJ et al. MJA 178: 427-432 2003

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