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 ProiettoUniversity of Melbourne

Department of Medicine

Repatriation Hospital

Austin Health

Heidelberg Victoria

THE EPIDEMIC

Prevalence

Overweight Obese Overweight plusObese

Men 48.2% 19.3% 67.5%

Women 29.9% 22.3% 52.1%

Cameron AJ et al MJA 178: 427-432 2003

The Scourge

2. NHMRC 2003

How Should we tackle the Obesity

Epidemic?

“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.

From the “NorthEast & Region”

Wednesday March 10 2004

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.

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

Impact of education on body weight

Cohort Study

Jeffery RW et al.Int J Obes Relat Metab Disord 19:30-39 1995

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.

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

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

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

What do you think the chances are of reducing this

exposure to negative messages ?

The Age 28 July 2006

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

Physical activity

The World Today - Tuesday, 29 June, 2004  12:30:00PM promises to spend on childhood obesity solutionsReporter: Alexandra KirkThe 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.

The Age 9 May 2007

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.

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.

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

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

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.”

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.”

Reduced Physical Activity:

3 types of activity Past Now(5,000,000 BC -1800) (1800-2010)

a) Obligatory + + + + -

b) Voluntary + +

c) Spontaneous + +

CHOICE

Can we engineer society to force increased physical

activity?

Probably not

Summary

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

Biological impediments to

limiting the obesity epidemic

NH&MRC 2003

Long term effects of weight loss – diet therapy

Diet Weight 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

-11.8 kg -4.1 kg

Meal replacement

-5.5 kg -6.5 kg

‘Popular’ diets Not known Not known

Long term effects of weight loss – Physical activity

Weight loss

1-2 years

Weight loss

> 2 years

Physical activity

- 1.8 kg - 1.3 kg

Diet plus activity

-7.5 kg - 3.1 kg

Long term effects of weight loss – Behaviour therapy

Weight loss

1-2 years

Weight loss

> 2 years

Behaviour therapy

- 4.7 kg -2.8 kg

Long term effects of weight loss –Surgery

Weight loss

1-2 years

Weight loss

> 2 yearsGastric bypass - 46 kg - 42 kg

Biliopancreatic bypass

- 53 kg - 54 kg

Non-adjustable gastroplasty

- 41 kg - 25 kg

Adjustable gastroplasty

- 31 kg - 34 kg

WHY THESE RESULTS?

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

Weight is Homeostatically

Regulated

Arcuate NucleusNPY CARTAGRP MSH Lateral

HypothalamusOrexin MCH

Paraventricular Hypothalamic NucleusOxytocin CRH

Brain Stem

FOOD INTAKE

ENERGY EXPENDITURE

Cerebral Cortex conscious will

Ghrelin

Leptin

CCKPYY3-36

GLP-1Oxyntomodulin

InsulinAmylin

PP

OpioidsDopamine Endocannabinoids

-

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?

Geldszus et al. Eur J Endocrinol 1996; 135: 659-62

Changes in Leptin levels with dieting

0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

0 60 120 180 240

Time (min)

Pla

sm

a C

CK

(p

mol/

L)

0

10

20

30

CC

K A

UC

(p

mol/L/4

h)

p=0.016

Week 0Week 9

Post- breakfast CCK release pre and post weight loss

Chearskul S. et al. American Journal of Clinical Nutrition, 87: 1238-1246, May 2008

Ghrelin levels after weight loss

8. Cummings 2002

What determines the weight that the homeostatic

mechanisms try to defend?

Weight is Genetically Determined

Genes and Obesity

BMI- Intrapair Correlations

Type CorrelationMen

Correlation Women

MonozygoticReared apartReared Together

0.700.74

0.660.66

DizygoticReared ApartReared Together

0.150.33

0.250.27

Stunkard AJ et al New Engl J Med 322:1483-7 1990

Twin A

Twin BAbd

omin

al F

at g

ain

Abdominal Fat gain

Effect of 100 days of overfeeding in 12 pairs of identical twins

Bouchard C et al New Engl J Med 322:1477-82 1990

So Obesity is genetic……

BUT……

Prevalence (cont)

1980 2000

ObeseBMI > 30

kg/m2

7.1% 18.4%

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

Obesity is more prevalent among lower socioeconomic groups

How can these contradictory results be

explained?

Obesity is more prevalent among lower

socioeconomic groups

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

Published 2009 Penguin Books London

How could social inequality cause

obesity?

Psychoneuroendocrinology 32: 824-33 2007

Prevalence (cont)

1980 2000

ObeseBMI > 30

kg/m2

7.1% 18.4%

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

Levin BE et al Am J Physiol 278:R231-R237 2000

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.

CONCLUSION 2 The optimistic view

We will limit the obesity epidemic by identifying and avoiding the environmental (dietary) triggers to genetic obesity

UniMelb ObesityAustin Health –Weight Control Clinic PhysiotherapyAustin Health – Department of Respiratory Medicine RMH– Metabolic Disorders ClinicAustralian Centre for Science, Innovation and Society Royal Women’s HospitalBariatric Surgery (AH/ WH) School of Population Health - Key

Centre Women's Health/Public Health

Centre for Adolescent Health School of Behavioural ScienceCentre for Meolecular, environmental, genetic andanalytical epidemiologyCentre for Community Child Health School of NursingCentre for Health, Exercise and Sports Medicine SVH HospitalCSIRO Molecular & Health Technologies St Vincents InstituteDepartment of Economics Victorian Centre of Excellence for

Eating DisordersEating Disorders Foundation Walter and Eliza Hall InstituteFaculty of Land and Food Resources Western Hospital Obesity ClinicMercy Hospital For Women Lymphoedema ClinicMetabolic Disorders Centre (A/H)Northern Hospital Healthy Eating ClinicPaediatric Obesity (RCH)Physiology