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Challenges to tacking the obesity epidemic: Why public health approaches do not work Joe Proietto University of Melbourne Department of Medicine Repatriation.

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Presentation on theme: "Challenges to tacking the obesity epidemic: Why public health approaches do not work Joe Proietto University of Melbourne Department of Medicine Repatriation."— Presentation transcript:

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 OverweightObeseOverweight plus Obese Men48.2%19.3%67.5% Women29.9%22.3%52.1% Cameron AJ et al MJA 178:

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

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:

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

17 The Age 28 July 2006

18 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

19 Physical activity

20 The World Today - Tuesday, 29 June, :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.

21 The Age 9 May 2007

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

23 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.

24 Katie M Mallam,et al BMJ 327:

25 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.”

26 Moodie ML, Carter RC, Swinburn BA, Haby MM. The cost-effectiveness of Australia's Active After-School Communities program. Obesity (Silver Spring) Aug;18(8): 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.”

27 Reduced Physical Activity: 3 types of activity PastNow (5,000,000 BC -1800) ( ) a) Obligatory b) Voluntary + + c) Spontaneous + +

28 CHOICE

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

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

31 Biological impediments to limiting the obesity epidemic

32 NH&MRC 2003

33 Long term effects of weight loss – diet therapy DietWeight loss 1-2 years Weight loss > 2 years Ad lib low fat-3.9 kg-2.7 kg Low energy-6.7 kg-1.1 kg Very low energy kg-4.1 kg Meal replacement -5.5 kg-6.5 kg ‘Popular’ dietsNot known

34 Long term effects of weight loss – Physical activity Weight loss 1-2 years Weight loss > 2 years Physical activity kg- 1.3 kg Diet plus activity -7.5 kg- 3.1 kg

35 Long term effects of weight loss – Behaviour therapy Weight loss 1-2 years Weight loss > 2 years Behaviour therapy kg-2.8 kg

36 Long term effects of weight loss –Surgery Weight loss 1-2 years Weight loss > 2 years Gastric bypass - 46 kg- 42 kg Biliopancreatic bypass - 53 kg- 54 kg Non-adjustable gastroplasty - 41 kg- 25 kg Adjustable gastroplasty - 31 kg- 34 kg

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

38 Weight is Homeostatically Regulated

39 Arcuate Nucleus NPY CART AGRP  MSH Lateral Hypothalamus Orexin MCH Paraventricular Hypothalamic Nucleus Oxytocin CRH Brain Stem FOOD INTAKE ENERGY EXPENDITURE Cerebral Cortex conscious will Ghrelin  Leptin  CCK PYY 3-36 GLP-1 Oxyntomodulin Insulin Amylin PP Opioids Dopamine Endocannabinoids -

40 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?

41 Geldszus et al. Eur J Endocrinol 1996; 135: Changes in Leptin levels with dieting

42 CCK AUC (pmol/L/4h) p=0.016 Week 0 Week 9 Post- breakfast CCK release pre and post weight loss Chearskul S. et al. American Journal of Clinical Nutrition, 87: , May 2008

43 Ghrelin levels after weight loss 8. Cummings 2002

44 What determines the weight that the homeostatic mechanisms try to defend?

45 Weight is Genetically Determined

46 Genes and Obesity

47 BMI- Intrapair Correlations TypeCorrelation Men Correlation Women Monozygotic Reared apart Reared Together Dizygotic Reared Apart Reared Together Stunkard AJ et al New Engl J Med 322:

48 Twin A Twin B Abdominal Fat gain Effect of 100 days of overfeeding in 12 pairs of identical twins Bouchard C et al New Engl J Med 322:

49 So Obesity is genetic…… BUT……

50 Prevalence (cont) Obese BMI > 30 kg/m 2 7.1%18.4% Cameron AJ et al. MJA 178:

51 Obesity is more prevalent among lower socioeconomic groups

52 How can these contradictory results be explained?

53 Obesity is more prevalent among lower socioeconomic groups

54 The current explanations are that: 1.There are more junk food outlets in underprivileged areas. 2.There is an inverse relation between energy density and energy cost. 3.The high energy density and palatability of sweets and fats are associated with higher energy intakes. However all of this ignores the intrinsic regulation of body weight

55 Published 2009 Penguin Books London

56

57 How could social inequality cause obesity?

58 Psychoneuroendocrinology 32:

59 Prevalence (cont) Obese BMI > 30 kg/m 2 7.1%18.4% Cameron AJ et al. MJA 178:

60 Levin BE et al Am J Physiol 278:R231-R

61 CONCLUSION 1 The Pessimistic view To overcome the powerful biological mechanisms causing and maintaining obesity we would need to recreate an environment where food is limited and physical activity is obligatory. Such a society is unthinkable in a free democratic country.

62 CONCLUSION 2 The optimistic view We will limit the obesity epidemic by identifying and avoiding the environmental (dietary) triggers to genetic obesity

63 UniMelb Obesity Austin Health –Weight Control ClinicPhysiotherapy Austin Health – Department of Respiratory MedicineRMH– Metabolic Disorders Clinic Australian Centre for Science, Innovation and Society Royal Women’s Hospital Bariatric Surgery (AH/ WH)School of Population Health - Key Centre Women's Health/Public Health Centre for Adolescent HealthSchool of Behavioural Science Centre for Meolecular, environmental, genetic and analytical epidemiology Centre for Community Child Health School of Nursing Centre for Health, Exercise and Sports Medicine SVH Hospital CSIRO Molecular & Health TechnologiesSt Vincents Institute Department of Economics Victorian Centre of Excellence for Eating Disorders Eating Disorders FoundationWalter and Eliza Hall Institute Faculty of Land and Food ResourcesWestern Hospital Obesity Clinic Mercy Hospital For Women Lymphoedema Clinic Metabolic Disorders Centre (A/H) Northern Hospital Healthy Eating Clinic Paediatric Obesity (RCH) Physiology


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