TODAY

© T. M. Whitmore

TODAY• Nutrition Transition Theory: How does this

all come together?

• Food Futures: Will there be enough food for the 21st century? Reasons for concernIssues around raising outputs

© T. M. Whitmore

Related historic processes of change• Interconnected “Transitions”

Demographic Transition (DT) Stages of change in mortality and fertility

=> population growth over time Regional differences-geography

Epidemiologic Transition (ET) Shift in the patterns of causes of death

over time Regional differences-geography

Nutrition Transition Shifts in dietary and physical activity-

inactivity patterns Regional differences-geography

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The Nutrition Transition’s “Stage 1: “Collecting Food”

• Hunter gatherersHigh in carbohydrates and fiber and low

in fat, especially saturated fatActivity patterns are very high with little

obesityStages 1-2 of DT First phase in ET

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The Nutrition Transition’s “Stage 2: “Famine”

• Early agriculture and contemporary least developed areas generallyDiet becomes much less varied and

subject to larger variations and periods of acute scarcity of food

Little change in activity levels Stages 1-2 of DT First-Second phases in ET

© T. M. Whitmore

The Nutrition Transition’s “Stage 3: “Receding Famine”

• Scientific agriculture, early industrialization, and contemporary developing areasConsumption of fruits, vegetables, and

animal protein increases, and starchy staples become less important in the diet

Activity patterns start to shift and inactivity and leisure becomes a part of the lives of more people

Stages 2-3 in DT Second/Third Phases of ET

© T. M. Whitmore

The Nutrition Transition’s “Stage 4: “Nutrition-related Non-

communicable Disease (NR-NCD)”

• Associated with “modern” industrial lifestylesA diet high in total fat, cholesterol, sugar

, and other refined carbohydrates and low in polyunsaturated fatty acids and fiber

Often accompanied by an increasingly sedentary life

Stage 4 in DT Third Phase of ET

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The Nutrition Transition’s “Stage 5: “Behavioral Change”

• “Post-modern” industrial lifestylesA new dietary pattern => changes in

diet associated with the desire to prevent or delay degenerative diseases and prolong health

May be associated with increased “recreational” or health related exercise

Stage 4 in DT Third Phase of ET

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Food Futures reasons for concern I:

Population Growth•Population growth to 8-10 billion by

2050 (50% more than today!)

•All in less developed world (China = India each ~ 1.5 b)

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Reasons for concern II: Dietary transitions

•Moving up on the food chainTraditional diets => ~2400 kcal;

10% animalImproved diets => ~3000 kcal; 25%

animal

• Increased animal fraction => 4-5 times more animal feed (plant material) needs to be produced

•Overall need ~ 2x current harvest to get improved diet by 2050 for everyone

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Reasons for concern III:Changes in agriculture

• Increases in pollution, erosion, and decreases in water availability potentially => Slow growth or even decrease

•Already slowing rates of growth of grain production per capita

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Can we raise Output? 4 major areas of concern

1.Photosynthesis and crop productivity limits

2. Land, water, and nutrient (NPK) limits

3. Agroecosystems and biodiversity4. Environmental change

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1) Photosynthesis & crop productivity limits

• There is an energetic limit: Photosynthesis is < 5% efficient in

converting sunlight to vegetative matter (even less if water or nutrients are short)

One way to address this is to improve the harvest index (= edible part/total biomass)

This is an area of possible progress traditional wheat 20 - 30% green revolution wheat 35 - 50%

© T. M. Whitmore

1) Photosynthesis & crop productivity limits

• There is an energetic limit: Photosynthesis is < 5% efficient in

converting sunlight to vegetative matter (even less if water or nutrients are short)

One way to address this is to improve the harvest index (= edible part/total biomass)

This is an area of possible progress traditional wheat 20 - 30% green revolution wheat 35 - 50%

© T. M. Whitmore

2) Land & soil limits I

• Agricultural land limits~ 1.5 giga (109) ha now cultivated and

1.6 giga ha (rainfed) potentially usableMost area available for expansion in S.S.

Africa & S. America savanna

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2) Land limits II• Land needed per-capita

Traditional vegetarian diet => 0.7-0.8 ha /capita

Chinese diet (2800 kcal; 15% animal) ~ 1.1 ha/capita

Rich Western diet ~ 4.0 ha/capita (much wasted and

high meat fraction)Better diet with some animal protein

~ 1.5-3.0 ha/capitaif 10 b people in 2050 =>

need 800 million ha to 3 gig ha (3000 million)

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2) Land limits III• If 10 b people in 2050 =>

Need 800 million ha to 3 gig ha (now use 1.5 gig ha)

• Thus, no absolute limit due to amount of land if diet not excessive & all available land used – AND food can be moved from surplus areas to deficit areas

• Regionally per-capita land availability is more problematic for 2050OK in Latin AmericaAdequate in Sub-Saharan Africa & Mid-

EastProblematic in South & East Asia

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2) Water limits I• Water: – in most systems water is the most

important limit most yearsPhotosynthesis uses/needs lots of water

also add evaporation and transpiration250 - 500 mm water needed per ha for

low-yielding crops 800 - 1000 mm water needed by high

yielding crops• Current irrigation

~ 250 million ha (only 8 m ha in 1800)~ 17% of all agriculture landCreates 40% of all food

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2) Water limits II• Current Water Use

Currently 5-7% of all available fresh water runoff used for agriculture

Even if water use only grew to match population => by 2050 agriculture will need 1/3 of all

available fresh water

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2) Water limits III• Crop and animal water use efficiency

Small grains and pulses => 0.25 m3 of water /million joules energy

to humans (or about 1 liter per kcal)Animals via grain and feed =>

25.4 m3 water/m joules energy to humans (100x more!) or ~ 100 liters per kcal

© T. M. Whitmore

2) Water limits IV• Water use in diets

Vegetarian diet (2500 kcal/day) => 0.9m – 1.2 million liters/capita/year

Rich world diets (more kcal and more animal foods) => >> 2.0 m l/capita/year

Improved diets (more kcal and more animal foods than traditional vegetarian) => ~ 2 million l/capita/year

So – 10 b people => 20,000 m3 water or ~ 2/3 of ALL global

runoff (assumes 2000 m3/capita/yr)

Demographic Transition Model

Nutrition Patterns 1 & 2Nutrition Patterns 3, 4, & 5

Nutrition Patterns 1 & 2 Nutrition Patterns 3, 4, & 5

New York Times

New York Times

Stages of Health, Nutritional, and Stages of Health, Nutritional, and Demographic ChangeDemographic Change

Focus on famine alleviation/prevention

Focus on family planning,infectious disease control

Chronic diseases predominate

Reduced fertility, aging

Focus on medical intervention, policy initiatives, behavioral change

Focus on healthy aging spatial redistribution

Demographic Transition

Epidemiologic Transition

Nutrition Transition

Receding pestilence, poorenvironmental conditions

Reduced mortality,changing age structure

High prevalence infectious disease

Diet-related noncommmucable

diseases predominate

Receding famine

High prevalence undernutrition

High fertility/mortality

Source: Popkin, Barry M. ( 2002) Public Health Nutrition 5:93-103.

2

4

3

5

Stages of the Nutrition Transition

Urbanization, economic growth, technological changes for work, leisure, & food processing, mass media growth

Pattern 3Receding Famine

Slow mortality decline

•increased fat, sugar, processed foods

•shift in technology ofwork and leisure

Pattern 4Degenerative Disease

accelerated life expectancy,shift to increased DR-NCD,increased disability period

•reduced fat, increased fruit, veg,CHO,fiber

•replace sedentarianism with purposeful changes

in recreation, other activity

Pattern 5Behavioral Change

extended health aging,reduced DR-NCD

MCH deficiencies, weaning disease,stunting

•starchy, low variety, low fat,high fiber

•labor-intensive work/leisure

obesity emerges,bone density problems

reduced body fatness,improved bone health

Source: Popkin, Barry M. ( 2002) Public Health Nutrition 5:93-103.

0

100

200

300

400

500

600

700

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Average daily caloric intake of added fats and sugars in the USA

Source: Source: USDA/Economic Research Service

2,500

3,000

3,500

4,000

4,500

1900 1920 1940 1960 1980 2000

Average caloric intake in USA: 1909-2004

Source: USDA/Center for Nutrition Policy and Promotion, March 3, 2006

0

20

40

60

80

100

120

140

160

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Average per capita daily calories (net) from fruits and vegetables in US

0

50

100

150

200

250

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Average daily calorie intake of red meat and chicken in USA

Source: Source: USDA/Economic Research Service