From the Food Security Forum 2014: Good food, good health: delivering the benefits of food security in Australia and beyond - 17 March 2014

1. The Silent Manipulator: Protein and the Burden
of Obesity in Australia
1
David Raubenheimer
Leonard P Ullman Chair of Nutritional Ecology
Faculty of Vet Science | School of Biological Science | Charles Perkins Centre

2. Nutritional Ecology is ….
• Ecological / evolutionary approach to nutrition
- focus on how nutrition mediates the relationship between animal & environment
- to determine health and wellbeing
Animal Biology
Environment
NUTRITION
health
lifespan
reproduction
etc.

3. health
lifespan
reproduction
etc.
health
lifespan
reproduction
etc.
Aims for the talk
NUTRITIONAL
GEOMETRY
Animal Biology
Environment
NUTRITION
ECONOMIC$
HUMAN APPETITE
OBESITY
• Introduce Nutritional Geometry: approach for studying these interactions
• Show how it has been used to understand:
1.
2.
3.
4.

4. Carbohydrate
Protein
excessC
deficit P
• Nutrient requirements
• Foods
• Feeding
- nutritionally balanced foods
- nutritionally imbalanced foods
• The challenge of dietary imbalance
Nutrient space
1) Nutritional Geometry: brief intro

5. Carbohydrate
Protein
prioritise C
prioritiseP
• Measuring how appetite responds to
dietary imbalance

6. e.g.lifespan
- or contour plot
Protein
Carbohydrate
- response surface
• Consequences

7. • How does the human appetite respond to dietary imbalance?
2) Human appetite
?

8. - humans prioritise P over F + C
• Meta analysis: 26 published trials
model
Gosby et al. (2013) Obesity reviews.
• Experiments in Oxford, Sydney & Jamaica
prioritiseP

9. • Can protein prioritisation help understand the global rise in obesity?
Source:AustralianInstituteofHealthandWelfare
3) Obesity
Australia 1980-2008

10. Protein
Carbohydrate+fat
14% P12.5% P
(1.5%)
- a small change in % P in foods will result in a large change in the
amount Carbs + Fat eaten
- for example, a 1.5% decrease in % P
14% increase in C + F eaten
-> Called the “Protein Leverage Hypothesis” (PLH)
- could this help explain the obesity
epidemic?
• Very likely:

11. 0 10 20 30 40 50 60
0
20
40
60
80
Energy intake (kj/day)
Protein (% kj)
Fat(%kj)
5000
6000
7000
8000
9000
10000
11000
[0]
[20]
[40][60]
(10:30:60)
1) Energy intake increases with decreasing %P
Two predictions of PLH
- Yes!

12. Prediction 2) Dietary % P has decreased with the rise in obesity
Data:FAOSTAT2010
- e.g. Australia
year
Protein(%energy)
- Yes!

13. 4) Economics
• If we prioritise protein, why do we select low-P diets?
?

14. Source:AustralianInstituteofHealthandWelfare
• A clue: obesity is more prevalent among low-income groups
- suggests economics might drive the consumption of low-P diets

15. 0 10 20 30 40
0
20
40
60
80
100
Protein g/100g
Fat+carbohydrateg/100g
0.6
0.8
1
1.2
1.4
1.6
1.82
2.2
1) Protein is more expensive than fats and carbs
$/100g
Brooks et al. (2009) Obesity reviews.
Three predictions
- 106 supermarket foods
- price increases with % P
- not with fats & carbs
• Test
• Result
- compared the separate
contributions to the price
of each g of Pro, Fat and Car
- suggests an economic incentive
to eat low P foods
• Conclude
cheap expensive
cheap

16. Prediction 2). Low SES groups eat low-protein diets
- 14 diet surveys of low SES
indigenous Australian communities
- most have low % P relative
to recommended range
• Aboriginal study
• Compared with Australian
recommendations (AMDR)
[With Aboriginal Nutrition Project Node]

17. Prediction 3). Low protein diets are associated with high energy intake
- yes!

18. CONCLUSIONS
Economic pressure
Reduced dietary % protein
Increased energy intake
Obesity
Obesity as an issue
of “nutrient security”
PROTEIN LEVERAGE