Dietary Regimes

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DIETARY REGIMES

Dominant patterns of food consumption have changed substantially as human societies evolved during tens of thousands of years of gathering and hunting, millennia of traditional pastoralism and settled farming, and a century of modern intensive agriculture. As a result, nearly 90 percent of humanity now enjoys at least an adequate food supply, and an increasing share of the world's population now worries about excess, rather than about shortages, of food.

Diets of Foraging Societies

The enormous diversity of foraging societies–ranging from maritime hunters with relatively easy access to highly nutritious aquatic animals to foragers in arid environments where tubers and seeds provided the bulk of food energy–means that there has never been a single typical gatherer-hunter diet. Societies exploiting the constant presence or regular migrations of mollusks, fatty fish (cod, salmon), and marine mammals (seals, whales) had by far the highest intake of both animal protein and lipids. These maritime foragers could have derived 30 to 50 percent of their food energy from animal protein. The only land foragers who could have approached that pattern, at least seasonally, were the cooperative hunters of megaherbivores; the best example of this strategy is mass killings of North American bisons by driving them over precipices. Given the typically low success rates in hunting the fast-running mid-size and small herbivores living on grasslands and in forests, most foragers had only a limited supply of animal foods. And, as nearly all small and most midsize animals are very lean, their diets were particularly short of fat.

Archaeologists have used remains and nutrient analyses of wild plant and animal foods consumed by foragers that survived into the twentieth century to estimate the dominant composition of prevailing pre-agricultural diets. These reconstructions conclude that plant foods, generally consumed within hours after being gathered, supplied 65 to 70 percent of all food energy. Proteins made up about a third of food energy (a share nearly three times as high as that recommended at the end of the twentieth century), and lipids about 20 percent. Average intakes of vitamins and minerals were generally well above the modern recommended daily allowances (RDA). These conclusions may not be representative of all foraging societies, because of the limited number of examined archaeological sites and because the foraging societies that survived into the twentieth century did so in mostly marginal environments. These marginal environments include, counterintuitively, tropical rain forests where hunting success is low, as most animals are arboreal, and hence relatively small and inaccessible in high canopies.

Pre-Industrial Diets

Archaeological findings and written documents offer a wealth of information about the composition of diets in antiquity, but translating these accounts into quantitative summaries of average or typical intakes is very difficult. Information about crop yields and animal productivity cannot be converted into average supply rates because of large, and highly variable, post-harvest food losses. Perhaps the only permissible generalization in accord with documentary and anthropometric evidence is the absence of any clear upward trend in per capita food supply during the millennia of traditional pre-industrial farming. In fact, stagnation or deterioration of food supply had not been uncommon. A reconstruction of ancient Mesopotamian ration lists indicates that daily energy supplies between 3000 and 2400 b.c.e. were about 20 percent above the early-twentieth-century mean for the same region. Similarly, the Han dynasty records show that during the fourth century b.c.e. a peasant was expected to provide each of his five family members with nearly half kilogram of grain a day, the rate equal to the North Chinese mean during the 1950s.

As the following examples illustrate, better information available for the last four centuries of the second millennium does not show any substantial nutritional improvements until the latter half of the nineteenth century. Annual per capita grain and meat supply in Rome fell by 25 to 30 percent during the seventeenth century. At the end of the eighteenth century, Sir Frederic Morton Eden found that the poorest English peasants consumed little or no milk or potatoes, no oatmeal, and seldom any butter, but occasionally a little cheese; he noted that even bread, their chief staple, was in short supply. Similarly, a third of the rural population in Eastern Prussia could not afford enough bread as late as 1847.

Diets of most pre-industrial populations were thus highly monotonous, not very palatable, and barely adequate in terms of basic nutrients. In most of Europe pre-industrial diets were dominated by bread (mostly dark, often with little or no wheat flour), and included coarse grains (oats, barley, buckwheat), turnips, cabbage, and, after 1570, potatoes. These ingredients were served in thin soups and stews, with evening meals indistinguishable from breakfasts and midday food. Similarly, in Asian peasant diets cereals–millet, wheat, rice, and after 1530, corn–supplied more than four-fifths of all food energy. Major sources of protein included soybeans in East Asia and lentils and chickpeas in the South. Millet, tubers such as cassava and yams, and legumes like peanuts were the staples of sub-Saharan Africa, and corn and beans were dominant throughout pre-Colombian America. Quinoa and a huge variety of potatoes were essential for survival in the Andean environment.

Vegetables and fruits enlivened the monotony of cereal and legume staples, but, unless preserved by pickling or drying, they were only seasonally abundant in temperate climates. Common European vegetables included turnips, cabbages, onions and carrots, while apples, pears, plums, and grapes brought the largest fruit harvests. Cabbages, radishes, onions, garlic, and ginger were the main vegetables consumed in China, and pears, peaches, and oranges were favorite fruits. Two quintessential Mesoamerican vegetables, tomatoes and peppers, became cultivated worldwide after 1600.

Typical pre-industrial meat consumption was very low, averaging no more than 5 to 10 kilograms per year, and roasts and stews were usually eaten only during festive occasions. Consequently, animal foods provided less than 15 percent of all dietary protein, and saturated animal fats supplied only around 10 percent of all food energy. Low meat consumption persisted not only during the early phases of European modernization in the nineteenth century, but into the twentieth century as well. Median annual meat intake in France was only about 20 kilograms per capita during the 1860s, and it was barely above 10 kilograms per capita in England. Monotonous diets, major consumption inequalities in both regional and socioeconomic terms, and recurrent food shortages and even famines persisted until the nineteenth century in Europe and well into the twentieth century in Asia and Africa, leaving the majority of peasants in all traditional farming societies with food supplies below optimal levels necessary for healthy and vigorous life.

Diets in the Age of Mechanized Agriculture

Major dietary change got under way in Europe only in the mid-nineteenth century and its scope ranged from eliminating any threat of famine to the founding of restaurants and emergence of the grande cuisine. Slow decline in the average consumption of staples was accompanied by growing intakes of animal foods and sugar. Cheaper imports of cane sugar and the introduction of the diffusion process to produce sugar from beets after 1860 in Europe and North America made refined sucrose easily obtainable for the first time in human history. This period of rapid dietary change led Ernst Engel (1821–1896), a German statistician, to formulate the eponymous law stating that the poorer a family, the higher its share of total expenditure spent on food. The law remains valid today–for nations as well as families: While an average American family spends only about one-seventh of its disposable income on food, the percentage is still more than 40 in China's cities.

The pace of Western dietary change accelerated after World War II as increasingly mechanized agriculture, supported by high energy subsidies and relying on new high-yielding crops, began producing surpluses of food. Mechanized agriculture improved the quality and variety of food, and supplied both staples and fancy foodstuffs at relatively decreasing prices. Foodstuffs that were previously too expensive or simply inaccessible began appearing in everyday diets. Chilled shipments of out-of-season fruits and vegetables and a growing trade in ocean fish and specialty foodstuffs eventually erased the seasonal availability of all but a few perishable plant species and diffused food items whose consumption was previously confined to specific areas (such as cactus pears, litchi, salmon, and sea bass).

Diets in the Twenty-First Century

Average per capita food supply at the beginning of the twenty-first century is in excess of 3,000 kilocalories per day in all Western nations and very close to 3,000 kilocalories per day in Japan. More than 30 percent, and in some circumstances even more than 40 percent, of all food energy comes from lipids, annual meat consumption is in excess of 70 or even 100 kilograms per capita, and in comparison to all pre-industrial diets, the modern Western diet is too high in sodium and too low in indigestible fiber. Incredibly, in spite of the surfeit of food and the common fortification of such staples as flour, many people in Western societies have micronutrient deficiencies, and several million people in North America go hungry.

The actual food energy requirement in modern, largely sedentary societies is only about 2,000 kilocalories per day, and the huge gap between the supply and the need explains both a great deal of food waste and the unprecedented extent of obesity that is being incessantly, and not very successfully, combated by ubiquitous dieting. Western diets in general, and obesity in particular, have been associated with the rise of such widespread "civilizational" diseases as cardiovascular illnesses and diabetes. The Mediterranean diet has been advocated as a healthy alternative, but the average intakes of Mediterranean populations have been shifting in the direction of less healthful Northern diets with declining consumption of bread, fruit, potatoes, and olive oil.

An excessive quantity of inexpensive food is accompanied by a still-increasing diversity of food supply brought by extensive intra-and intercontinental trade (including perishable foodstuffs ranging from tuna fish to grapes), by the commingling of food traditions in nations with large immigrant populations, and by the globalization of many previously spatially restricted food and beverage items such as leavened breads, pizza, sushi, beer, and wine. At the same time, more single-person households, high rates of female employment, and reduced willingness to cook have brought an astonishing rise in the consumption of fast foods whose dominant ingredients are saturated fat (in hamburger, pizza, and taco empires) and refined sugar (in doughnut and coffee shops). The picture of modern food customs would not be complete without noting extensive food faddism, cultism, and quackery, practices ranging from megavitamin regimens to pseudo-scientific diets (from vegan to macrobiotic), and consumption of both natural and synthetic food supplements (from echinacea extracts to zinc lozenges). A new concept, made possible by genetic engineering, is the use of food as medicine (called "nutraceuticals").

In contrast to the rich world's food surpluses, average daily food supplies below 2,000 kilocalories per capita are still common in the world's most impoverished countries where some 95 percent of the world's more than 800 million malnourished people can be found (about 200 million in India, 140 million in China). Dietary transitions that took more than a century in the West are being compressed into just a few decades in many rapidly modernizing Asian countries. They are marked, on one hand, by declining consumption of cereal grains and even more rapid reduction in the consumption of legumes and, on the other hand, by rising intakes of plant oils, animal foods (meat as well as aqua-cultured fish and crustaceans), fruits, and sugar. Post-1980 China is the best example of this process as it has moved from a barely adequate diet dominated by staple grains and basic vegetables to a total per capita supply nearly equaling the Japanese mean (about 2800 kilocalories per day in 2000).

In spite of the indisputable globalization of tastes, national and regional food preferences are evident around the world and food taboos, only weakly held in the West in the early twenty-first century, remain strong among nearly two billion Muslims and Hindus. Further homogenization of tastes will be accompanied by further diffusion of "exotic" foodstuffs and by the development of hybrid cuisines and new eating habits. Regardless of the unpredictable specifics of future dietary changes, there is no doubt that these new global trends will demand more resources for production of higher-quality and specialty foods–more fertilizers and pesticides for perfect fruit, high-protein feed for aqua-cultured carnivorous fish–and for their worldwide distribution. Manipulating these trends through pricing is hardly an option in a world where commodity prices have been in a prolonged and nearly universal decline. Public education about healthy nutrition is imperative, but it is an uphill task in societies suffused with gluttony-promoting advertisement and hedonist values, and lacking dietary discipline.