The Nutrition Transition

Evolution is transition. Fueled by ideas, war, scientific breakthroughs, and chance, the relationship of humans with their environment is in constant change, in an endless quest for equilibrium.

The Nutrition Transition

Data from the past decade and projections for the next 20 years (Murray and Lopez, 1996) indicate a continuing rise in the contribution of no communicable diseases to mortality rates in developing countries, where a large proportion of the global poor lives.

The Nutrition Transition

Robert W. Fogel and Lorens A. Helmchen, The growth in material wealth has been matched by changes in body size over the past 300 years, especially during the twentieth century.

The Nutrition Transition

Per capita availability of calories more than doubled in this period in France, and increased by about 50% in Great Britain, where caloric supply was 30% larger than that in France at the beginning of the period.

The Nutrition Transition

The role of genes in the human adaptation to rapid environmental changes has been postulated for many decades, but only with advances in molecular genetics can we identify with some clarity the interactions between genes and environmental components such as diet.

Sabtu, 26 November 2011

Traditional agriculture's

In comparison to foraging, traditional farming nearly always required higher inputs of human energy (and later also of animal labor), but it could support higher population densities and provide a more reliable food supply. Whereas foraging (except for maritime hunting) could support no more than a few people per 100 hectares (ha) of territory used for gathering and hunting, early traditional agricultures managed to support at least one person/ha of arable land (Fig. 3.1). By the end of the 19th century China’s nationwide mean was above five people/ha, and double cropping of rice and wheat in the most fertile areas could yield enough to feed 12–15 people/ha (Smil, 1994).
                                                                    Modern farming
                                                   Traditional farming
                                    Shifting farming
0.0001 0.001 0.01 0.1 1 10
Population density (people/ha)
Figure 3.1
Comparison of carrying capacities of the principal modes of human food production showing that farming can support 10–10 more people than foraging (based on Smil, 2000). 
The need for higher energy inputs explains why so many foraging societies kept delaying adoption of permanent cultivation and why shifting farming – a less intensive method of cultivation alternating short (1–3 years) cropping periods with much longer (a decade or more) fallow spells – was practiced so extensively. In spite of many regional and local differences there were many fundamental similarities that persisted across the millennia of traditional farming. Above all, these agricultures were entirely renewable; photosynthetic conversion of solar radiation produced food for people, feed for animals, recyclable wastes for the replenishment of soil fertility, as well as wood (often turned into charcoal) for smelting metals needed to make simple farm tools. But the renewability of traditional farming was no guarantee of its sustainability. In many regions poor agronomic practices gradually depleted soil fertility or caused excessive soil erosion or desertification. These changes brought lower yields or even the abandonment of cultivation. But in most regions traditional farming progressed from extensive to relatively, or even highly, intensive modes of cultivation.
 Except for small-scale cultivation of tubers (above all cassava) in the tropics and the Inca’s reliance on potatoes, all of the Old World’s traditional agricultures, as well as plowless Mesoamerican societies, shared their dependence on cereal grains. Cereal cultivation was supplemented by legumes, tubers and oil, fiber and, in some agricultures, also feed crops. After the domestication of draft animals the traditional crop cycles always started with plowing. Primitive wooden implements were used for millennia before the introduction of metal moldboard plows, 2000 years ago in China, but only some 17 centuries later in Europe. Plowing was followed by harrowing and by manual seeding. Harvesting also remained manual (sickles, scythes) until the introduction of grain reapers before the middle of the 19th century. Wheat cultivars had diffused worldwide from the Near East, rice from Southeast Asia, corn from Mesoamerica and millets from China.
Continuous primacy of grains in crop cultivation is due to the combination of their relatively high yields (two or three times higher than legume harvests), good nutritional value (high in filling, easily digestible carbohydrates, moderately rich in proteins), relatively high energy density at maturity (at 13–15 MJ/kg roughly five times higher than for tubers), and low moisture content ( 14%) suitable for long-term storage. Dominance of a particular species has been largely a matter of environmental conditions and taste preferences. Without understanding the nutritional rationale for their actions all traditional agricultures combined the cultivation of cereal and legume grains thus assuring complete amino acid supply in largely vegetarian diets. The Chinese planted soybeans, beans, peas, and peanuts to supplement millets, wheat and rice. In India protein from lentils, peas, and chickpeas enriched wheat and rice. In Europe the preferred combinations included peas and beans with wheats, barley, oats, and rye, in West Africa peanuts and cowpeas with millets, and in the New World corn and beans.
The principal means of agricultural intensification included more widespread and more efficient use of draft animals, increasing fertilization and regular crop rotations, more frequent irrigation in arid regions, and multicropping in the places where cli-mate could support more than a single crop per year. The use of draft animals (horses, mules, oxen, water buffaloes, camels, donkeys) eliminated the most exhaustive field work and it also sped up considerably many farmyard tasks (threshing, oil pressing), improved the quality of plowing (and later also of seeding), allowed for drawing of water from deeper wells for irrigation. The introduction of collar harness, invented in China about two millennia ago, iron horseshoes, and heavier animal breeds made field work more efficient (Smil, 1994). Feeding larger numbers of these animals eventually required further intensification to produce requisite feed crops.
Irrigation and fertilization moderated, if not altogether removed, the two key constraints on crop productivity, shortages of water and nutrients. Unaided gravity irrigation could not work on plains and in river valleys with minimal stream gradients; the invention and introduction of a variety of simple mechanical, animal- and people-driven water-lifting devices (mostly in the Middle East and China) solved this challenge (Molenaar, 1956). Fertilization involved recycling of crop residues and increasingly intensive applications of animal and human wastes. Extensive practices used no manure, whereas peak manuring rates in the 19th century Netherlands and in the most productive provinces in China surpassed 20 t/ha. Green manuring, cultivation of leguminous cover crops (clovers, vetches) which were then plowed under, was widely used in Europe ever since ancient Greece and Rome, and it has also been widely employed in east Asia (Smil, 2001). Even so, nutrient deficiencies commonly limited traditional crop productivity.
Growing of a greater variety of crops lowered the risk of total harvest failure, discouraged the establishment of persistent pests, reduced erosion, and maintained better soil properties. Crop rotations were chosen to fit climatic and soil conditions and dietary preferences. In poor societies they could substantially improve food self-sufficiency and food security at the local level. Traditional varieties of crops and their rotation schemes were enormous. For example, Buck’s (1937) survey of Chinese farming counted nearly 550 different cropping systems in 168 localities. The adoption of new crops – most notably the post-1500 introductions of such New World staple as corn and potatoes and such versatile vegetables as tomatoes and peppers – had an enormous impact on food production throughout the world. In spite of these innovations preindustrial agricultures brought only very limited improvements in average harvests. For example, European wheat yields, except in the Netherlands and the UK, did not begin to rise decisively before the last decade of the 19th century (Smil, 1994).
Traditional farming also provided no more than basic subsistence diets for most of the people. Even during fairly prosperous times typical peasant diets, although more than adequate in terms of total food energy, were highly monotonous and not very palatable. In large parts of Europe bread (mostly dark, and in northern regions with little or no wheat  our), coarse grains (oats, barley, buckwheat), turnips, cabbage, and later potatoes, were the everyday staples. Typical rural Asian diets were, if anything, even more dominated by rice or coarse grain (millet, buckwheat). In many cases traditional peasant diets also contained less animal protein than did the earlier intakes with higher consumption of wild animals, birds, and aquatic species. This qualitative decline was not offset by a more equitable availability of basic foodstuffs: major consumption inequalities, both regional and socioeconomic, persisted until the 19th century. The majority of people in all traditional farming society had to live on food supplies that were below the level required for a healthy and vigorous life and different kinds of malnutrition were common.
Documentary and anthropometric evidence does not demonstrate any consistent upward trend in per capita food supply across the millennia of traditional farming. Regardless of the historical period, environmental setting and prevailing mode of cropping and intensification, no traditional agriculture could consistently produce enough food to eliminate extensive malnutrition. More importantly, no preindustrial agriculture could prevent recurrent famines. Droughts and  oods were the most common natural triggers, and as a recent study demonstrates these natural disasters often represented the worst imaginable climatic teleconnections arising from the El NiƱo-Southern Oscillation (ENSO) whose effects are felt far beyond the Pacific realm (Davis, 2001). The combined (and never to be accurately quantified) toll of large-scale famines that repeatedly swept late 19th century India and China, and that also severely affected parts of Africa and Brazil, amounted to tens of millions of casualties.
In China in the 1920s peasants recalled an average of three crop failures brought by such disasters within their lifetime that were serious enough to cause famines (Buck, 1937). Some famines were so devastating that they remained in collective memory for generations and led to major social, economic and agronomic changes: the famous collapse of Phytophthora-infested Irish potato crops between 1845 and 1852, or the great Indian drought-induced famine of 1876–79. The world’s most devastating famine, in China between 1958 and 1961, was only secondarily a matter of drought; the primary causes lie in the delusionary Maoist policies (Smil, 1999a).

Sabtu, 19 November 2011

Modern farming

New energy sources and three intertwined strands of innovation explain most of the success of modern farming. In contrast to traditional agriculture's, nonrenewable fossil fuels and electricity are essential inputs in modern farming. They are needed to build and operate agriculture machinery whose nearly universal adoption mechanized virtually all field and crop-processing tasks. The second key innovation is the use of fossil energies and electricity to extract and synthesize fertilizers and pesticides. The third key advance was to develop and diffuse new crop varieties responsive to higher inputs of water and nutrients. These innovations brought higher and more reliable yields, they displaced draft animals in all rich countries and greatly reduced their importance in the poor ones. The replacement of muscles by internal combustion engines and electric motors and the substitution of organic recycling by inorganic fertilizers have drastically cut labor needs in agriculture and led to huge declines in rural populations and to the worldwide rise of urbanization. For example, in the US rural labor fell from more than 60% of the total workforce in 1850 to less than 40% in 1900, 15% in 1950, and a mere 2% since 1975 (US Bureau of the Census, 1975).
 Fertilizers made the earliest, and also the greatest, difference. The use of chemically treated phosphates became common after the discoveries of new rock deposits in Florida in 1888, and in Morocco in 1913. After 1850 nitrogen from Chilean nitrates, supplemented later by the recovery of ammonium sulfate from coking ovens, provided the first inorganic alternative to organic recycling. The nitrogen barrier was finally bro-ken by the invention of ammonia synthesis from its elements by Fritz Haber and the sub-sequent rapid commercialization of the process by Carl Bosch (Smil, 2001).
This invention allowed, for the first time in history, to optimize nitrogen inputs on large scale. Modern civilization is now critically dependent on the Haber–Bosch synthesis of ammonia. Recent global applications of nitrogen fertilizers to field crops – and also to permanent grasslands and tree (orchard, palm) and shrub (coffee, tea) plantations – have been in excess of 80 million tonnes (Mt) N/year, mostly in the form of urea (IFA, 2001; Fig. 3.2). The process currently provides the means of survival for about 40% of the world’s population. Only half as many people as are alive today could be supplied.
1950 1960 1970 1980 1990 2000
Figure 3.2
Post-1950 growth of nitrogen fertilizer production.

By traditional cultivation lacking any synthetic fertilizers and producing very basic, and overwhelmingly vegetarian, diets; and prefertilizer farming could provide today’s average diets to only about 40% of the existing population (Smil, 2001). Western nations, using most of their crop production for feed, could easily reduce their dependence on synthetic nitrogen by lowering their high meat consumption. Populous poor countries, where all but a small share of grain is eaten directly, do not have that option. Most notably, synthetic nitrogen provides about 75% of all inputs in China. With some 75% of the country’s protein supplied by crops, more than half of all nitrogen in China’s food comes from synthetic fertilizers.
In addition to nitrogen the world’s crops now receive also close to 15 Mt of phosphorus, and about 18 Mt of potassium a year (IFA, 2001). This massive use of fertilizers has been accompanied by the expanding use of herbicides used to control weeds, and pesticides to lessen insect and fungal infestations. Pesticide use has often been much maligned and many of these chemicals, especially following improper applications, undoubtedly leave undesirable residues in harvested products, but their use has helped to reduce the still excessively large preharvest losses.
Farming mechanization was first accomplished in the US and Canada. Its most obvious consequence was the precipitous decline in agricultural labor requirements. For example, in 1850 an average hectare of the US wheat needed about 100 hours of labor; by 1900 the rate was less than 40 hours/ha, and 50 years later it sank below 2 hours/ha (US Bureau of the Census, 1975). Until the 1950s agricultural mechanization proceeded much more slowly in Europe, and in the populous countries of Asia and Latin America it really started only during the 1960s. Today’s agriculture operates with more than 26 million tractors of which about 7 million are in developing countries (FAO, 2001). Mechanization also completely transformed crop processing tasks (threshing, oil pressing, etc.) and fuel and electric pumps greatly extended field irrigation. The global extent of crop irrigation more than quintupled between 1900 and 2000, from less than 50 to more than 270 million hectares, or from less than 5% to about 19% of the world’s harvested cropland (FAO, 2001). Half of this area is irrigated with pumped water, and about 70% is in Asia.
The key attribute common to all new high-yielding varieties (HYV) is their higher harvest index, that is the redistribution of photosynthate from stalks and stems to harvested grain or roots. Straw:grain ratio of wheat or rice was commonly above 2:1 in traditional cultivars, whereas today’s typical ratio is just 1:1 (Smil, 1999b). HYVs receiving adequate fertilization, irrigation, and protection against pests did responded with much increased yields. This combination of new agronomic practices, introduced during the 1960s, became widely known as the Green Revolution and the term is not a misnomer as the gains rose very rapidly after the introduction of these rewarding, but energy-intensive, measures. Higher reliance on intensively cultivated grain monocultures, narrowing of the genetic base in cropping and environmental impacts of agricultural chemicals have been the most discussed worrisome consequence of this innovation, but all of these concerns can be addressed by better agronomic practices (Smil, 2000).
Aggregate achievements of modern farming have been impressive. Between 1900 and 2000 the world’s cultivated area expanded by about one-third, but the global crop
Figure 3.3
Post-1950 growth of average cereal grain yields epitomizing the rising productivity of modern
farming (plotted from data in FAO, 2001) 

Harvest rose nearly six fold. This was because of a more than fourfold increase of ave-rage crop yields made possible by a more than 80-fold increase of energy inputs to field farming (Smil, 2000). But even though the global mean harvest of all cereals more than doubled between 1950 and 2000 (Fig. 3.3), there are still large gaps between average yields and best (not record) harvests (FAO, 2001). Global corn harvest aver-ages just over 4 t/ha but farmers in Iowa are bringing in close to 10 t/ha. Average wheat yield (spring and winter varieties) is 2.7 t/ha but even national averages in the UK, the Netherlands or Denmark Western are more than 8 t/ha today. Extensive diffusion of HYV of rice raised the global mean yield to almost 4t/ha, whereas Japan or China’s Jiangsu average in excess of 6t/ha.
Higher cereal and tuber yields freed more agricultural land for no staple species, above all for oil and sugar crops. Higher cereal yields have also allowed for more and more efficient animal feeding in rich countries where the abundance of meat and dairy products has made high-protein diets much more affordable. HYVs also raised the food output of many developing countries above subsistence minima. However, a substantial gap still divides the typical agricultural performances of rich and poor countries, and, given the far greater social inequalities in the latter group, this production disparity translates readily into continuing large-scale presence of malnutrition in scores of African, Asian, and Latin American countries.

Jumat, 11 November 2011

Current food production and supply & Global food production

Current food production and supply
A word of caution first: only a minority of food production and consumption figures readily accessible in FAO databases and widely used in assessments of global food availability and needs is derived from the best available national statistics which may themselves contain many inaccuracies even when prepared by the most advanced statistical services of developed countries. Although some of the developing countries (notably China and India) have massive statistical bureaucracies and issue a great number of regular reports many of their numbers are known to be highly inaccurate.
For example, for many years Chinese official statistics listed less than 100 million hectares (Mha) as the total of the country’s cultivated land (about 95 Mha until 2000) although many people in Beijing bureaucracy and some foreign experts knew that total was vastly undervalued. China now admits to having 130 Mha of cultivated land (National Bureau of Statistics, 2000) and the best remote sensing studies based on classified US information indicate 140, or even 150Mha (Smil, 1999c). This change means, of course, that every official yield figure for the past 20 years is inaccurate. And, obviously, countries with protracted civil wars (several in Africa, Colombia) or with a disintegrating central government (Indonesia) are in no position to collect and publish any reliable agricultural statistics. Given these realities it is not surprising that most of the numbers for most of the developing nations that appear in FAO databases are just the best expert estimates made in the organization’s Rome headquarters (FAO, 2001).
These realities mean that both exaggerations and underestimates are common and that often the resulting numbers may not be accurate re ections of the actual situation but are best used in order to derive fair approximations of the current state of agricultural affairs. It should also be noted that according to the FAO developed countries numbered 1.3 billion people in the year 2000, the developing ones 4.7 billion, a division slightly different from that used by the UN’s population experts (UN, 2001). These realities should be kept in mind when considering the following brief review of current food output and availability.
Global food production
Today’s food producers fall mostly into four uneven categories. Several thousand large agribusiness companies, most of them in North America and Europe, control extensive areas of food and feed crops and highly concentrated meat production in giant feedlots. Their production goes directly to large-scale food processors or is destined for export. Several million highly mechanized family-owned farms in af uent countries rely on intensive practices to achieve high crop and animal productivity. Tens of millions of the most successful farmers in the most productive agricultural regions of many developing countries (e.g., China’s Jiangsu and Guangdong or India’s Punjab) use generally high levels of the best locally available inputs in order to pro-duce food beyond their family’s and region’s need. And hundreds of millions of subsistence peasants, either landless or cultivating small amounts of often inferior land, use inadequate inputs, or no modern means of production at all, to grow barely enough food for their own families.
Cereal grains continue to dominate the global crop harvest. Their annual output is now just above 2 billion tonnes. Developing countries produce nearly 60% of all grain, with twice as much rice as wheat (about 570 vs. 270 Mt in 2000), but in per capita terms their output (about 260 kg/year) is only about 40% of the developed countries mean (660 kg/year). Most of the poor world’s grain (more than 85%) is eaten directly, whereas most of the rich world’s grain (more than 60% during the late 1990s) is fed to animals. Consequently, actual per capita supply of processed food cereals is still about 25% higher in developing countries (165 vs. 130 kg/year), re ecting simpler diets dominated by grain staples. Not surprisingly, rich countries enjoy even higher per capita disparities in production of nonstaple crops, with the differences being particularly large for sugar (30 vs. 15 kg/year) and meat (almost 80 vs. 25 kg).
Per capita consumption of legumes has been declining for several generations in every country where pulses previously played a critical nutritional role. Only India’s annual per capita consumption of legumes remains above 10 kg/year (FAO, 2001). In contrast, no other crop diffusion in agricultural history has been as rapid and as economically far-reaching as the cultivation of soybeans for feed. US soybean plant-ings rose from a few thousand hectares in the early 1930s to more than 20 Mha since the early 1970s, and they now produce more than 50Mt/year. Brazilian soybean production rose even faster, from a negligible total in the early 1960s to more than 20Mt by the early 1990s. These two countries now produce two-thirds of the global soybean harvest, virtually all of it for animal feed.
Rising af uence combined with concerns about healthy diets has resulted in a steady growth of fruit production. Global fruit output has tripled since 1950, but this does not convey the unprecedented variety of fruits, including many tropical imports as well as winter shipments of subtropical and temperate species from the southern hemisphere, that are now available virtually year-round in all rich countries. The trend of rising fruit production recently has been most obvious in rapidly modernizing China where fruit harvests (now also increasingly for export) rose more than 10-fold (from less than 7 to more than 70 Mt) between 1980 and 2000 (National Bureau of Statistics, 2000).
With global annual output of nearly 500Mt cow’s milk is the most important animal  food. Annual output of all kinds of milk amounts to about 570 Mt. Per capita avail-abilities of dairy products are large in North America and Western Europe (in excess of 250kg/year) and negligible in traditionally nonmilking societies of East Asia. Pork, with about 80 Mt/year and rising, is by far the most important meat worldwide, with China and the US slaughtering the largest number of animals. Total meat output, including poultry, is now over 200 Mt a year, prorating to almost 80 kg/capita in rich countries and to about 25 kg/capita in the poor world. Poultry production (near 60 Mt/year) is now ahead of the combined beef and veal output and it will continue to rise. Consumption of hen eggs is now at more than 40Mt a year, and recent rapid growth of aquaculture (its combined freshwater and marine output is now close to 30Mt a year, equal to nearly a quarter of ocean catch) has put cultured fish, crustaceans, and mollusks ahead of mutton.
After a period of decline and stagnation the global marine catch began rising once more during the mid-1990s and is now close to 100 Mt/year but major increases are highly unlikely. A conservative assessment of the global marine potential concluded that by 1996 the world ocean was being fully fished, with about 60% of some 200 major marine fish resources being either overexploited or at the peak of their sustainable harvest (FAO, 1997). Consequently, if long-term marine catches were to be kept at around 100 Mt a year then 50 years from now the population growth would cut per capita fish supply by more than half compared to the late 1990s level. The importance of this harvest is due to its nutritional quality. During the late 1990s the world’s aver-age per capita supply of some 14 kg of marine species contained only a few percent of all available food energy, but it supplied about one-sixth of all animal protein. More importantly, aquatic species provide more than a third of animal protein to at least 200 million people, mostly in east and southeast Asia (FAO, 2001).

Kamis, 03 November 2011

Food supply

The world’s recent edible crop harvests prorate to about 4700 kcal/day per capita, but nearly half of the cereal production, worth about 1700 kcal/day, is fed to animals, and postharvest crop losses amount to some 600 kcal/day (Smil, 2000). This leaves about 2400 kcal/day of plant food and with some 400 kcal/day from animal foods (including aquatic products) the average per capita availability adds up to roughly 2800 kcal/day, well above a generous estimate of average needs of 2200 kcal/capita. Similarly, the world’s mean daily protein supply of 75 g/capita is well above the needed minimum. An egalitarian global civilization would thus have no problems with adequate nutrition. Equitable distribution of available food among the planet’s more than 6 billion people would provide enough protein even if the global food harvests were to be some 10% lower than they are today.
 In the real world these adequate global means hide, as do other global averages, large inter- and intranational differences. All Western nations enjoy uniformly high per capita food availabilities averaging about 3200 kcal/day. Their mean per capita supply of dietary protein is about 100 g/day, including about 55 g from animal foods. No elaborate calculations are needed to conclude that the average per capita food supply is more than adequate in all af uent countries. Because the actual requirements of mostly sedentary populations are no more than 2000–2200 kcal/day it is no exaggeration to label the resulting food surpluses (at least 1000–1200 kcal/day and up to 1600 kcal/day) as obscene.
After all, even when leaving aside the large energy and protein losses in animal feeding, at least 30% of all food available at the retail level in Western societies is wasted! Average Western diets in general, and the North American one in particular, also contain excessive amount of lipids, which now supply 30–40% of all food energy compared to the average of less than 20% in developing countries and to shares below 15% in the poorest societies (FAO, 2001). Surfeits of food energy and lipids are the two key nutritional factors implicated in the increase of obesity and diabetes and in a high frequency of cardiovascular disease (see Chapters 9–11). Fortification of many foodstuffs (from our to juices) with vitamins and minerals and a fashionable use of dietary supplements (including recurrent megadose manias) by increasingly health-conscious segments of the aging population would suggest that there are very few micronutrient deficiencies. This is, unfortunately, not true as clinical and biochemical studies in the US show that intakes of calcium, iron, and zinc are not adequate in some groups (Pennington, 1996).
 Given the obviously high incidence of overweight and obesity it is not surprising that hunger and malnutrition in af uent nations have received so little attention, but their extent is far from negligible (Riches, 1997). Poppendieck’s (1997) estimates that 22–30 million Americans cannot afford to buy enough food to maintain good health have been questioned, but even the most conservative estimates acknowledge that 10–20 million poor Americans could not feed themselves adequately without assistance, and that far from all of them are actually receiving it. The coexistence of undernutrition and widespread obesity is thus one of the most peculiar features of America’s current nutritional situation.
Japan, which is highly dependent on food imports, is the only high-income country with per capita food supply below 3000kcal/day (the rate has been steady at about 2900 kcal/day for nearly two decades). Specific features of the country’s food con- sumption include the already noted world’s highest per capita intake of aquatic products, exceptionally high intakes of soybeans (eaten mostly as beancurd), and very low con-sumption of sugar. Average food availability in China is now almost as high as in Japan (close to 2800kcal/day), but in spite of impressive post-1980 diversification (Fig. 3.4) its variety and quality is still much lower. Moreover, unlike in a highly egalitarian Japan, China’s mean hides large differences between coastal and interior provinces.
 India and Indonesia in the late 1990s were, respectively, at about 2400 and 2600 kcal/day. This would have provided adequate nutrition for everybody only if the two countries had a perfectly egalitarian access to food; in reality, highly skewed income distribution makes India the country with the largest number of undernour-ished people (FAO, 2000). Many sub-Saharan African countries average less than2200 kcal/day, some even less than 2000 kcal/day, and these obviously inadequate food supplies are re ected in the world’s shortest life expectancies at birth. Even when adequate in terms of total energy and protein, typical diets in most developing coun-tries are monotonous. And, unlike in af uent nations where nearly all traces of sea-sonal food supply have been erased by international trade, diets in many poor countries still strongly re ect the seasonality of plant harvests or fish catches.

25                                               Fruit
                                                                              Aquatic products
1970 1980 1990 1999
Figure 3.4
Dramatic changes in China’s average per capita food supply brought by Deng Xiaoping’s post-1980 economic reforms exemplify a rapid dietary transition in a modernizing country. Based on data from State Statistical Bureau (1980–2000); these figures exaggerate actual meat consumption (see the text for details).