Global diets: Just the facts

Production team

Vegetables and fruits

Vegetables and fruits form a variable part of diets throughout the world.

On a population basis, vegetables (which here exclude roots and tubers, and pulses) and fruits, supply less than 5 per cent total energy in most countries. In some areas of China, Oceania, and the Caribbean, vegetables and fruits provide over 10 per cent total energy; in southern Europe they provide about 6 per cent total energy. Industrialised diets average about 5 per cent total energy from vegetables and fruits. Consumption is lowest in parts of eastern Europe and in the poorer countries of Africa and Asia. Consumption is higher where, for climatic reasons, there is abundant supply, and lower where there is short or seasonal supply, and in parts of Africa and Asia where diets are impoverished.

Consumption overall does not greatly vary as a function of economic development. Generally, vegetables and fruits are low in energy and are good sources of fibre and of vitamins and minerals. In some developing countries, where food is scarce or diets are monotonous, the inclusion in the diet of even small amounts of vegetables and fruits containing b-carotene and vitamin C help prevent scurvy.

Sugars

Sugars and sweeteners include sugar (sucrose), dextrose (glucose), corn syrup, high fructose corn syrup, and artificial sweeteners (e.g. aspartame and acesulphame -K). Table sugar (sucrose) occurs naturally in fruit, sugar beets and sugar cane. The plant is cut, crushed to release juice, and then boiled into syrup. This syrup is then processed to make the final products (molasses, brown sugar, white sugar, confectioner's sugar, etc).

To make white sugar, the liquid sugar syrup is filtered to whiten it, then it is milled into granules. In developed countries, sugar is increasingly becoming a food ingredient for processed foods, whereas in developing countries, it is more likely to be bought as a straight product. Other sweeteners are based on the simple sugars (e.g. glucose and fructose) that occur naturally in every living organism. They are a source of sweetness in fruit and honey and can turn brown with heating, contributing to the colour of bread crust and toast. Corn syrup consists mostly of glucose, and is a sweet, thick liquid made by treating cornstarch with acids or enzymes. Alternatively, corn syrup can be treated with enzymes to convert some of its dextrose to fructose, which results in High Fructose Corn Syrup (HFCS).

Artificial sweeteners are made by chemical reactions. They provide the sweetness of sugars without as many calories, so they are often used for diet products or as sugar substitutes. Saccharin (Sweet 'N Low) was the first artificial sweetener, a coal tar derivative which is 350 times sweeter than sugar. Aspartame (Equal, NutraSweet) is 160 times sweeter than sugar and is made up primarily of two amino acids. Sugar, corn syrup, and other refined sweeteners provide calories, but no vitamins, minerals, or protein. Someone getting 15 per cent of their calories from such a source would have to get 100 per cent of their nutrients from the other 85 per cent of their food. Sugar and other refined sugars may also be implicated in obesity, tooth decay, and potentially heart disease. But artificial sweeteners may be associated with other health risks.

Americans consume about 30kg of sucrose per year. That figure is down from about 46kg per year in 1970, but the decrease has been more than made up for with high fructose corn syrup (HFCS) and dextrose (glucose). About 71kg of all refined sugars are produced in the United States per person per year, an increase of 28 per cent since 1983. Interestingly that's just when the use of aspartame started skyrocketing. In other words, it appears that artificial sweeteners have not replaced the sugars, but may have stimulated America's sweet tooth. Globally, there has been a small decrease in the share of calories obtained from sugars and sweeteners since 1970, but the figures are complicated by the role of low calorie sweeteners. Consumption in industrialised countries decreased from the early 1970s, when sugars and sweeteners accounted for about 14.3 per cent of total calories consumed, to the late 1990s, when it was about 13.4 per cent. Consumption in developing countries, by contrast, increased during the same period - from 6.5 per cent in the early 1970s to 7.2 per cent in the late 1990s, perhaps reflecting increasing incomes and a move towards Western-style patterns of consumption.

Roots

Roots (such as cassava), tubers (such as potatoes, yams and taro) and plantains (bananas) are non-cereal starchy foods that are important in diets in some parts of the world. They are variable in their nutrient content: roots and tubers contain various amounts of starch: sweet potatoes about 12 per cent, potatoes about 20 per cent, yams about 30 per cent, and cassava 25-50 per cent, by weight

Parts of the world where starchy roots and tubers form a large proportion of the diet are the Pacific islands, where they contribute a regional average of about 20 per cent total energy, and sub-Saharan Africa, where they contribute a regional average of about 15 per cent total energy. The potato is now the most important starchy food in the temperate regions of America and Europe. They are a staple food in parts of the Andes. Plantains and other cooking bananas are a staple food in some parts of sub-Saharan Africa, and bananas are eaten as a fruit in most countries.

Pulses

Pulses, also known as legumes, are the most important plant sources of protein, and are also good sources of fibre and many vitamins, minerals and other bioactive compounds. They include beans, peas, lentils and groundnuts (peanuts). Those that have matured and dried on the plant are perhaps the most commonly consumed; pulses include broad beans, chickpeas, kidney beans, lentils, peanuts, soya beans.With cereals, they are the staple protein source for populations that consume little or no food of animal origin.

On a population basis, consumption of pulses varies between very small amounts (where food of animal origin is the main source of protein) to 10 per cent or more of total energy. Pulses are consumed in a wide variety of ways; examples include Japanese and Chinese bean curd (tofu), Chinese mung bean sprouts, Mexican chilli and refried beans, Indian dahl, Middle Eastern falafel and humus, Indonesian cultured soya bean cakes (tempeh), Cuban black beans and rice, Boston baked beans, Italian minestrone, Swedish pea soup, and US peanut butter. Soya foods include soya milk and flour, tofu, tempeh, textured vegetable protein, and the many products that can be prepared from these items.

Pulses, together with nuts and seeds, have been estimated to provide about 5.6 per cent total energy in economically developing countries, and 2.4 per cent in developed countries. Pulses make the greatest contribution to dietary energy supply in some areas of sub-Saharan Africa, followed by the Middle East, Asia and North Africa. In some areas of China, they provide as much as 10 per cent total energy. In Central America, they are also a relatively important part of the diet. In Brazil, they are usually eaten with rice and provide 5 per cent total energy. Consumption is lowest in Europe, Australia, New Zealand and North America.

Nuts

Nuts and seeds, common in the diets of pre-agricultural peoples, are dense in energy and are good sources of unsaturated fats, protein, fibre and microconstituents. There is only poor data on consumption of nuts and seeds on a population basis.Nuts are the dried fruits of trees; most are enclosed in hard shells.

Examples of nuts consumed in human diets include walnuts, hazelnuts, almonds, chestnuts, pine nuts, pistachio nuts and pecans. Some other foods thought of as nuts, including Brazil nuts, macadamia nuts and cashews, are actually seeds. Seeds come from the fruits of plants and contain the embryo and food supply for the next plant generation. Most seeds have hulls or shells that are softer than those of nuts; in some cases the shells can be eaten. Seeds commonly consumed in human diets include sunflower, sesame, pumpkin, poppy and squash seeds.

Nuts and seeds are important sources of protein, particularly in diets that do not contain meat. The protein content of nuts and seeds ranges from 10 to 25 per cent by weight. Nuts and seeds have a very high fat content and are therefore energy dense; for nuts, typically, 70-90 per cent total energy comes from fat. Nuts and seeds are also rich sources of unsaturated oils, vitamins and minerals.

Meat

Meat, poultry, fish and eggs make up variable amounts of most diets. Red meat (from beef, lamb and pork) is central in most diets in developed societies, as are poultry (notably from chickens, as well as ducks, turkeys, and other birds). Meat from non-domesticated animals and birds is generally now less significant in most diets. Consumption of fish and of seafood is highly variable.

On a population basis, consumption of some or all of these foods varies between nothing (in vegetarian societies) to negligible amounts (in low-income societies) to 20 per cent or more of total energy (notably in some richer developed countries). Meat and poultry intake is low in most African countries, India and other low-income Asian countries, typically contributing less than 3 per cent total energy. Worldwide, meat and poultry contribute, on average, 9 per cent total energy. The highest intakes are in Denmark, where meat and poultry contribute 24 per cent total energy, and in Australia, New Zealand, Argentina and Bermuda, where these foods provide around 20 per cent of total energy.

Consumption of fish and seafood also varies widely in different parts of the world.As a general rule, meat consumption increases with economic development. For example, between 1980 and 1987, meat intake in Japan rose from around 18 g/day to 71 g/day per person. Between the 1960s and the 1990s, poultry consumption has risen in almost every country, with a worldwide average increase of 50 per cent.

Egg consumption has been reported to be around six eggs per person per week in the USA. Egg consumption has increased by 100-200 per cent in Asia over the past 25 years but is still lower in most Asian countries than in the USA.

Meat, poultry, fish and eggs are good sources of protein and various vitamins and minerals. The fat content of meat and poultry varies widely; meat from domesticated animals typically contains substantial amounts of fat, particularly saturated fats. Fatty fish are good sources of essential polyunsaturated fats. Eggs are a source of protein. Non-domesticated animals are a significant source of meat among some populations in extreme northern climates, in North Africa, in Islamic countries and the Eastern Mediterranean and in some rural areas of the USA. There are important differences, particularly in fatty acid content and composition, between meats from domesticated animals and 'wild' meats. Offal is also a form of meat, but there is little epidemiological evidence specific to this group of meats.

Meat, poultry and fish contain around 20 per cent protein, by weight. The fat content of meat, poultry and fish ranges from a low of less than 4 per cent fat for lean poultry and some types of fish, to 30-40 per cent fat by weight for fatty meat from domesticated farmed animals fed on cereals (grains) and pulses (legumes). Wild meat is typically low in fat.Saturated fatty acids make up around 40-50 per cent of the total fatty acids in meat. In the USA, these meats have been reported to contribute around one-third of saturated fat intake.

Poultry contains a somewhat lower proportion of saturated fatty acids (35 per cent) and a higher proportion of polyunsaturated fatty acids (15-30 per cent as compared with 10 per cent). Fat from fish contains even less of saturated fatty acids (20-25 per cent) and oily fish are a rich source of omega-3 fatty acids. Intensively reared poultry and farmed fish contain more fat than free-ranging or wild equivalents. Meat and poultry are rich sources of the B vitamins B6 and B12, and of readily absorbable iron, zinc, selenium and fatty acids. Fish contains relatively lower levels of B vitamins and iron and zinc than meat and poultry, but oily fish are a rich source of retinol and vitamin D; fish are a good source of calcium when the bones are eaten. Eggs are moderate sources of protein and fat. The yolks of eggs are high in dietary cholesterol.

Herbs

Herbs, spices and condiments are part of diets worldwide. Many of them have known pharmacological and therapeutic properties relevant to human health, and most contain potentially potent bioactive compounds. Practically all diets include seasonings, flavourings, savours and sauces made from herbs, spices and other edible substances that have aromatic, pungent or other flavours, aromas and colours.Various herbs contain high levels of carotenoids and vitamin C.

Herbs and spices also contain very variable amounts of a number of bioactive compounds, whose relevance to human health is not yet fully understood. General knowledge of the therapeutic qualities of many herbs and some spices suggests that further human studies may yield evidence of a relationship with cancer. The fact that herbs, spices and condiments, by their nature, normally make up only a very small part by volume and weight of any diet is not in itself a reason to dismiss them as insignificant.

Consumption of herbs, spices and condiments varies greatly in different parts of the world. Consumption probably varies inversely with consumption of salt, which here is not classified as a condiment. Many traditional cuisines are typified by the use of herbs, spices and condiments, singly or in combination, mixed into food in cooking or at the table.

Herbs, spices, and condiments may have specific functions. For example, they may make dull, distasteful or decaying food palatable. They may make otherwise ordinary food delicious. They may be preservatives. Many herbs and spices are believed to have medicinal or tonic value and, in some societies, are mixed into meals in various combinations and quantities to prevent or treat common diseases. Many pharmaceuticals are derived from herbs and other plants, and traditional therapies typically make use of herbs as medicines.

Dairy produce

Milk from domesticated animals is consumed both by infants and adults in many cultures. Dairy products such as butter and cheese make up variable amounts of most diets. On a population basis, consumption of milk and dairy products varies between zero or practically zero, to 10 per cent or more of total energy. Milk and dairy products can be good sources of protein, vitamin D and calcium. Milk and dairy products from domesticated animals typically have a high fat and saturated fat content. Some or most of this fat may be removed in processing. Milk from a variety of animals has been used by humans as post-weaning food throughout history.

Cows' milk is most popular in European countries; goat, sheep and camels' milk are common in the Middle East. Water buffalo are used as a source of milk within Asia. As well as being consumed fresh, milk is also commonly processed into a wide variety of foods including cheese, fat products such as butter and ghee, and fermented products such as yoghurt.

As with meat, fish and poultry, milk and dairy products are not consumed universally and several population groups avoid or restrict some or all of these foods for religious, philosophical or health reasons.

On a worldwide basis, milk and dairy products contribute about 5 per cent total energy. Consumption is higher among traditional pastoral peoples in Africa, India and China, and people living in or originating from northern Europe. In these populations, milk and dairy products typically contribute around 10 per cent total energy and provide around 15-25 per cent dietary protein and fat intake. In the past 30 years, marked decreases in consumption have been seen in only a few countries in Central America, Africa and the Middle East. The increase in milk and dairy product consumption has been particularly marked in Japan and Korea.

Cereals

The major types of cereals (grains) are wheat, rice, maize (corn), millet, sorghum, barley, oats and rye. Cereals and the many foods made from them are the most important single food group in the world. They form the basis of diets in many different countries. In the developing world, cereals (and other starchy foods) generally make up most of dietary volume and energy. As societies become industrialised, diets generally become less bulky and more energy-dense, cereals supply less of the total energy, and cereals and cereal products become more refined and processed in other ways.

The few populations for whom cereals are not an important food group are pastoralist peoples, such as the Masai; hunters, including the Inuit and other arctic populations, who maintain their traditional way of life and diet; and populations in some regions of Oceania and sub-Saharan Africa where there is a high reliance on starchy roots, plantains and tubers. Rice is the main cereal eaten, followed by wheat and maize (corn).

More wheat is grown than rice on a global basis, but much wheat goes into animal feeds. Other cereals important in particular regions include millet and sorghum, eaten in parts of sub-Saharan Africa, South America and Asia, and rye, eaten in eastern and central Europe. Cereals are eaten in very many forms. None is eaten in an unprocessed raw state; even rice eaten as boiled grains has been milled to some degree, with its outer husk and bran removed. Many cereals are milled into flours of varying degrees of extraction of husk and germ, and then made into a vast variety of foods. Widely eaten cereal-based foods include leavened and unleavened breads (such as chapatti, tortilla and pitta), noodles, pasta, dumplings and gruels or porridges.

Source for nutritional information and diet facts: Food, Nutrition and the Prevention of Cancer: a global perspective (1997) a report commissioned by the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR).

US

US calorie consumption per person is up 20 per cent since the early 1970s to the world's highest - a third above the global average. Although the U.S. menu reflects the variety of typical industrialised countries, it is lower than the industrialised country average in cereals and higher in meats, sugar and sweeteners and dairy products.

Average daily calories per person: 3,654

Sahara

In this generally poor region where tens of millions are chronically undernourished, daily per capita consumption was 2,176 calories in 1995-97, 20 per cent below the global average. Cereals and roots still provide 70 per cent of calories. More costly foods that would add variety and nutrition are consumed at some of the world's lowest rates.

Average daily calories per person: 2,176

Latin nations

Among major developing regions, Latin America shows the least overall dependence on cereals and the greatest apparent dietary diversity. Since the early 1970s, consumption of cereals and starchy roots and pulses has decreased and diets now include more meat and poultry, sugar and sweeteners, dairy products and vegetable oils.

Average daily calories per person: 2,791

Europe

Despite a taste for sausages and cheeses, Europeans consume fewer calories than Americans, and diets more closely mirror industrialised country averages. Compared with the United States, cereal consumption is higher, though down since the 1970s - opposite the US trend. Diets have less sugar, but nearly 7 per cent of calories come from animal fats, twice the US level.

Average daily calories per person: 3,394-97.

Asia

Rising incomes and farm production have altered diets and steadily shifted this region's calorie consumption. Although rice and other cereals still account for 60 per cent of calories, that's down from 67 per cent in the early 1970s. The role of starchy roots (such as cassava), tubers (such as potatoes) and pulses (such as beans), have been halved.

Average daily calories per person: 2,648

Africa

Oil revenues have helped North African countries such as Egypt, Libya and Algeria boost average calorie consumption by nearly 40 per cent since the early 1970s. Cereals remain the primary source of calories, but cereal consumption has dropped slightly, while the share of calories from most other food groups has increased.

Average daily calories per person: 3,187

Source for global diet information: Economic Research Service, USDA, UN Food and Agriculture Organisation Agrostat database.