obesity and the economics of food choice
TRANSCRIPT
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Obesity and the economics Obesity and the economics of food choiceof food choice
Adam Drewnowski, PhDAdam Drewnowski, PhDDirector, Center for Public Health NutritionDirector, Center for Public Health NutritionDirector, UW Center for Obesity ResearchDirector, UW Center for Obesity Research
Professor of Epidemiology and Adj. Prof. MedicineProfessor of Epidemiology and Adj. Prof. MedicineSchool of Public Health and Community MedicineSchool of Public Health and Community Medicine
University of WashingtonUniversity of Washington
Food and Health Session, July 9, 2008Food and Health Session, July 9, 2008Population Health Congress, July 7Population Health Congress, July 7--9, 2008, Brisbane, Australia9, 2008, Brisbane, Australia
Is obesity an economic issue?Is obesity an economic issue?
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Food choices
Convenience
Variety
Obesity
How people choose foodsHow people choose foods
Energy density
Health
Taste
Cost
First questionFirst question
What is energy density of foods?What is energy density of foods?
•• Energy density defined as MJ/kgEnergy density defined as MJ/kg•• Energy values from databaseEnergy values from database•• Energy density is the Energy density is the inverseinverse of water of water
content content
3
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100water content (g/100g)
Ener
gy d
ensi
ty (M
J/kg
)
Fats Sweets Grains
grains
butter
oil
Energy density (MJ/kg) depends on thewater content of foods
Soft drinks
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100water content (g/100g)
Ener
gy d
ensi
ty (M
J/kg
)
Meat Dairy
meats
Energy density (MJ/kg) depends on thewater content of foods
cheese
milk
4
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100water content (g/100g)
Ener
gy d
ensi
ty (M
J/kg
)
Vegetables Fruit
Potato chips
Energy density (MJ/kg) depends on thewater content of foods
beans
Dry fruit
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100w ater content (g/100g)
Ener
gy d
ensi
ty (M
J/kg
)
Fats Sweets Grains Vegetables Fruit Meat Dairy
grains
butter
oil
vegetablesfruit
Potato chips
meats
Energy density (MJ/kg) depends on thewater content of foods
cheese
5
0
10
20
30
40
0 10 20 30 40 50 60 70 80 90 100w ater content (g/100g)
Ener
gy d
ensi
ty (M
J/kg
)
Fats Sweets Grains Vegetables Fruit Meat Dairy
grains
butter
oil
vegetablesfruit
Potato chips
meats
Energy density (MJ/kg) depends on thewater content of foods
cheese
Energy rich; nutrient poorEnergy rich; nutrient poor
Energy poor; nutrient richEnergy poor; nutrient rich
Food choices
Convenience
Variety
Obesity
How people choose foodsHow people choose foodsEnergy density
Health
Taste
Cost
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Second questionSecond question
Do energyDo energy--dense foods cost less?dense foods cost less?
•• Energy density defined as kcal/100gEnergy density defined as kcal/100g•• Energy cost defined as Energy cost defined as €€/1000 kcal/1000 kcal•• Energy values from databasesEnergy values from databases•• Mean national food prices in France Mean national food prices in France
0
200
400
600
800
1000
0.01 0.1 1 10 100 1000Energy cost (Euros/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
Energy density (kcal/100g) and energy cost (Euros/1000kcal) – INCA study
spreads
Log scale!
7
0
200
400
600
800
1000
0.01 0.1 1 10 100 1000Energy cost (Euros/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
sugar
desserts
soft drinks
Energy density (kcal/100g) and energy cost (Euros/1000kcal) – INCA study
0
200
400
600
800
1000
0.01 0.1 1 10 100 1000Energy cost (Euros/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
sugar
desserts
soft drinks
grains
bread
pasta
Energy density (kcal/100g) and energy cost (Euros/1000kcal) – INCA study
8
0
200
400
600
800
1000
0.01 0.1 1 10 100 1000Energy cost (Euros/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
sugar
desserts
milk
grainscheese
yogurtpasta
Energy density (kcal/100g) and energy cost (Euros/1000kcal) – INCA study
0
200
400
600
800
1000
0.01 0.1 1 10 100 1000Energy cost (Euros/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
sugar
desserts
milk
grainscheese
meat
pasta
Energy density (kcal/100g) and energy cost (Euros/1000kcal) – INCA study
9
0
200
400
600
800
1000
0.01 0.1 1 10 100 1000Energy cost (Euros/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
sugar
desserts
milk
grainscheese
fish/shellfish
foie gras
pasta
meat
Energy density (kcal/100g) and energy cost (Euros/1000kcal) – INCA study
0
200
400
600
800
1000
0.01 0.1 1 10 100 1000Energy cost (Euros/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
sugar
desserts
milk
grainscheese
fish/shellfishpasta
meat
vegetables
Energy density (kcal/100g) and energy cost (Euros/1000kcal) – INCA study
10
0
200
400
600
800
1000
0.01 0.1 1 10 100 1000Energy cost (Euros/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
sugar
desserts
milk
grainscheese
fruit
fish/shellfish
vegetables
nuts
pasta
Energy density (kcal/100g) and energy cost (Euros/1000kcal) – INCA study
0
200
400
600
800
1000
0.01 0.1 1 10 100 1000Energy cost (Euros/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
sugar
desserts
milk
grainscheese
fruit
fish/shellfish
vegetables
nuts
pasta
Wine/alcohol
Energy density (kcal/100g) and energy cost (Euros/1000kcal) – INCA study
11
0
2
4
6
8
10
0.01 0.1 1 10 100 1000Energy cost ($/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
sugar
desserts
milk
grainscheese
fruit
fish/shellfish
vegetables
nuts
pasta
Same price hierarchy in Seattle as in France
0
200
400
600
800
1000
0.01 0.1 1 10 100 1000Energy cost (Euros/1000kcal)
Ener
gy d
ensi
ty (k
cal/1
00g)
oil
butter
Are “junk” foods simply cheaper?
sugar
desserts
soda
grains
fruitfish
vegetables
High glycemic IndexHigh glycemic loadHydrogenated fatsTrans fatty acidsAdded sugarsAdded fatsEnergy dense foodsEmpty caloriesMinimal nutritional value
Low energy densityHigh satiating power AntioxidantsPhytochemicalsFiberCLAVitaminsMinerals
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Third questionThird question::
Do energyDo energy--dense dense dietsdiets cost less?cost less?
•• French INCA study conducted by AFSSAFrench INCA study conducted by AFSSA•• Sample of 1,985 adults; 7Sample of 1,985 adults; 7--day food diariesday food diaries•• National prices for 650 foods supplied by National prices for 650 foods supplied by
French government (INSEE); by market French government (INSEE); by market research agencies (SECODIP)research agencies (SECODIP)
•• Diet costs estimated in Diet costs estimated in €€/d/d•• Energy cost estimated as Energy cost estimated as €€//10MJ10MJ•• This is a measure of This is a measure of monetary exposuremonetary exposure
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10
Energy density (KJ/g)
Die
t cos
t (Eu
ros/
wee
k)
EI1
At each intake quintile, At each intake quintile, higher energy density = lower cost higher energy density = lower cost ((€€/wk)/wk)
INCA data 1998INCA data 1998
13
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10
Energy density (KJ/g)
Die
t cos
t (Eu
ros/
wee
k)
EI1
EI2
At each intake quintile, At each intake quintile, higher energy density = lower cost higher energy density = lower cost ((€€/wk)/wk)
INCA data 1998INCA data 1998
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10
Energy density (KJ/g)
Die
t cos
t (Eu
ros/
wee
k)
EI1
EI2
At each intake quintile, At each intake quintile, higher energy density = lower cost higher energy density = lower cost ((€€/wk)/wk)
EI3
INCA data 1998INCA data 1998
14
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10
Energy density (KJ/g)
Die
t cos
t (Eu
ros/
wee
k)
EI1
EI2
At each intake quintile, At each intake quintile, higher energy density = lower cost higher energy density = lower cost ((€€/wk)/wk)
EI3
EI4
INCA data 1998INCA data 1998
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10
Energy density (KJ/g)
Die
t cos
t (Eu
ros/
wee
k)
EI1
EI2
At each intake quintile, At each intake quintile, higher energy density = lower cost higher energy density = lower cost ((€€/wk)/wk)
EI3
EI4
EI5
INCA data 1998INCA data 1998
15
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10
Energy density (KJ/g)
Die
t cos
t (Eu
ros/
wee
k)
EI1
EI2
A drop in dietary energy density A drop in dietary energy density means higher diet cost means higher diet cost ((€€/wk)/wk)
EI3
EI4
EI5
INCA data 1998INCA data 1998
Fourth questionFourth question::
Do nutrientDo nutrient--rich rich dietsdiets cost more?cost more?
•• French INCA study conducted by AFSSAFrench INCA study conducted by AFSSA•• Sample of 1,985 adults; 7Sample of 1,985 adults; 7--day food diariesday food diaries•• National prices for 650 foods National prices for 650 foods •• Vitamin C intakes from nutrient data baseVitamin C intakes from nutrient data base•• Diet costs estimated in Diet costs estimated in €€/d/d•• Measures of Measures of dietary dietary and and monetary monetary exposureexposure
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0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000
Vitamin C (mg/wk)
Die
t cos
t (Eu
ros/
wee
k)
EI1
At each intake quintile, At each intake quintile, More vitamin C = higher cost More vitamin C = higher cost ((€€/wk)/wk)
INCA data 1998INCA data 1998
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000
Vitamin C (mg/wk)
Die
t cos
t (Eu
ros/
wee
k)
EI1
EI2
At each intake quintile, At each intake quintile, More vitamin C = higher cost More vitamin C = higher cost ((€€/wk)/wk)
INCA data 1998INCA data 1998
17
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000
Vitamin C (mg/wk)
Die
t cos
t (Eu
ros/
wee
k)
EI1
EI2
At each intake quintile, At each intake quintile, More vitamin C = higher cost More vitamin C = higher cost ((€€/wk)/wk)
EI3
INCA data 1998INCA data 1998
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000
Vitamin C (mg/wk)
Die
t cos
t (Eu
ros/
wee
k)
EI1
EI2
At each intake quintile, At each intake quintile, More vitamin C = higher cost More vitamin C = higher cost ((€€/wk)/wk)
EI3EI4
INCA data 1998INCA data 1998
18
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000
Vitamin C (mg/wk)
Die
t cos
t (Eu
ros/
wee
k)
EI1
EI2
At each intake quintile, At each intake quintile, More vitamin C = higher cost More vitamin C = higher cost ((€€/wk)/wk)
EI3EI4
EI5
INCA data 1998INCA data 1998
Fifth question:Fifth question:
Are lowAre low--cost energycost energy--dense diets dense diets preferentially consumed by low preferentially consumed by low
income persons?income persons?
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The relation between food, health and The relation between food, health and income is nothing newincome is nothing new
Engel’s Law (1867) Engel’s Law (1867) As incomes rise, so do food expenditures As incomes rise, so do food expenditures –– but the but the shareshare
spent on food declinesspent on food declines
USDA’s Economic Research Service Food Review, 23, 2000
Boyd Orr: UK 1937
0
5
10
15
20
25
30
35
40
<10 10-15. 15-20 20-30 30-40 40-50 50-70 >70
USDA 2000
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Foods as luxury goods: Foods as luxury goods: Boyd Orr 1937Boyd Orr 1937
FruitFruit
FishFish
VegetablesVegetables PotatoesPotatoes
SugarSugar
BreadBread
Lard, suetLard, suetMeatMeat
56
58
60
62
64
66
68
70
0-50 51-100 101-130
131-200
201-299
300
Income as % of poverty Education (years)
HEI
sco
re 1
994-
96
56
58
60
62
64
66
68
70
<12 12 to 16 16 >16
More education and income = better diets More education and income = better diets (USDA/CNPP data cited in (USDA/CNPP data cited in DrewnowskiDrewnowski & Specter, 2004)& Specter, 2004)
The USDA Healthy Eating Index (HEI) is a measure of diet quality
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Are food costs the key?Are food costs the key?Are poverty and obesity linked by the low cost of energyAre poverty and obesity linked by the low cost of energy--
dense foods?dense foods?
Drewnowski & Specter, Am J Drewnowski & Specter, Am J ClinClin NutrNutr 2004;79:62004;79:6--1616
Can living in the wrong neighborhood make you fat?
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Median incomes in King CountyKing County Census Tracts 2000 aggregated by zip codes
Fewer Starbucks more fast foods in South County
Data source: Washington State Geospatial Archive
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LegendNumber of Fast Food Rest Per Mile
2.83
1.0
0
Fast foods
Starbucks
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Density of grocery stores in Seattle-King County, WA
LegendKernel Density of Grocery Stores
2
0.8
0
Data source: Washington State Geospatial Archive, Corporate Websites and United States Census Bureau
Density of convenience stores in Seattle-King County, WA
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LegendNumber of Conv Stores Per Mile
2.7
1.5
0
Data source: Washington State Geospatial Archive
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Obesity rates by zip code (BRFSS data)
King County Zip CodesDiab Related Deaths per 100,000 (1999-2003)
28 - 39.9
40 - 59.9
60 - 89.9
90 - 120
Insufficient Sample (<50)
Water
Obesity
Diabetes deaths
Zip CodeObesity Prevalence
4.3 - 8.7
8.71 - 13.1
13.11 - 17.79
17.8 - 22.29
22.3 - 28.3
No Data
Obesity rates and real estate
BRFSS data aggregated from 1999-2002, Courtesy of PHSKC Planning and Evaluation
Burien, 98168: Median house value $143,500 Obesity rate 24.9%
$172,950
Madison Park and Capitol Hill, 98112: Median house value $466,000 Obesity rate 5.9%
$1.8 million
Bellevue, 98005: Median house value $343,400 Obesity rate 5.1%
$745,000
Kent, 98031: Median house value $182,900, Obesity rate 23.1%
$150,000
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Obesity rates and SEP (as measured by real estate)
R2 = 0.3928
0
5
10
15
20
25
30
100000 150000 200000 250000 300000 350000 400000 450000 500000
Median House Value (2000)
Perc
ent O
bese
by
Kin
g C
o Zi
p C
ode
Data source: PHSKC Planning and Evaluation Unit and United States Census Bureau
Seven-fold disparities in diabetes-related mortality rates by zip code
0
50
100
150
200
250
300
Age-
Adju
sted
Dia
bete
s-R
elat
ed M
orta
lity
Rat
e
Regionwide rate
050
100
150
Dia
bete
s R
elat
ed M
orta
lity
100000 200000 300000 400000 500000 600000Median Home Value
Assoc b/w Diab Related Mortality and Neighborhood Wealth
R2=0.42
Data from WA State death certificatesCourtesy of PH-SKC, Tacoma/Pierce Co Health Dept; Snohomish Health District
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Food choices
Convenience
Cost
Variety
Obesity
A complex storyA complex story
PleasureEnergy density
Health
Taste
Nutrient-dense foods cost more
High quality diets cost more
Rich people exercise more
Rich people are thin
Rich people have more resources
Rich people eat more costly diets
So what led to obesity?Poverty or excess ____ food?
Obesity: biology, behavior, society – and economics
Grains, fats, sugars cost less
Energy-dense diets cost less
Obese people eat unhealthy diets
Poor people have few resources
Poor people exercise less
Poor people are obese
Poor people eat cheaper diets
Thin people eat healthier diets
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Are the people of the UK Are the people of the UK inexorably becoming inexorably becoming
heavier simply by living in heavier simply by living in the Britain of today?the Britain of today?
The Foresight Report: Tackling Obesities: Future ChoicesThe Foresight Report: Tackling Obesities: Future Choices