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Diets evolve over time because of factors such as changes in food availability, food prices, and level of income. Traditional, largely plant-based diets are being replaced by diets that are high in sugars and animal fats and low in starches, dietary fibre, fruits, and vegetables. This transition, combined with a general trend towards a more sedentary lifestyle and a low level of physical activity, is an underlying factor in the risk of developing chronic diseases.
This text is a summary of: WHO/FAO
Diet, Nutrition and the prevention of chronic diseases
3.1 Introduction
The food consumption per person is often estimated based on national (sales) statistics that are averaged out over the entire population. In terms of energy content, expressed in kilocalories (kcal) per person per day, the average food consumption appears to have steadily increased in countries around the world.
On average, the amount of food consumed per person has increased by nearly 20% between the mid 1960s and late 1990s, reaching an estimated 2803 kcal per day. The increase has generally been even greater in developing countries. However, levels of consumption have remained nearly constant in sub-Saharan Africa and have fallen in countries in economic transition.
Table 1: Global and Regional per capita food consumption.
This increase in food consumption has been accompanied by a shift in dietary energy sources away from basic foods such as cereals and potatoes, and towards animal products and vegetable oils.
Table 2: Vegetable and animal sources of energy.
This text is a summary of: WHO/FAO
Diet, Nutrition and the prevention of chronic diseases
Section 3.2 Developments in the availability of dietary energy
As the overall food consumption is increasing, the fat content of the diet (including fats and oils contained in or added to foods) is also changing. Over the past three decades a remarkable increase in the intake of dietary fats and has taken place practically everywhere, except in Africa where consumption levels have stagnated. The fat consumption remains highest in parts of North America and Europe.
Table 3: Trends in the dietary supply of fat
The recommended share of dietary energy (in kcal) that should be derived from fats ranges from a minimum of 15% to a maximum of 35%. In 1990, however, energy from fats fell below the recommended minimum in several countries in sub-Saharan Africa and South Asia, whilst it exceeded the recommended maximum in many countries in Western Europe and North America.
Dietary fats are made up of different fatty acids depending on the food source. A growing proportion of fats are acquired from animal products which tend to be particularly high in saturated fats.
The consumption of certain types of vegetable oils is increasing in parts of the world. In particular, in developing countries, the intake of hardened margarines (that are rich in trans-fatty acids) is increasing because they do not need to be refrigerated.
As the demand for olive oil has increased, production has shifted from traditional methods to a more intensive form of cultivation, which might have negative effects on the environment. The development of new processes may enable the production of oil that has a healthy fatty acid composition.
This text is a summary of: WHO/FAO
Diet, Nutrition and the prevention of chronic diseases
Section 3.3 Availability and changes in consumption of dietary fat
The livestock sector is growing at an unprecedented rate as a result of population growth, rising incomes, and urbanization (which leads to better distribution network for a wider variety of animal products). Although the average consumption of animal products has strongly increased in countries such as Brazil and China, the levels are still well below that of North America and most other developed countries.
Table 4: Per capita consumption of livestock products
As diets become richer and more diverse, the high-value protein that the livestock sector offers improves the nutrition of the vast majority of the world. Livestock products not only provide high-value protein but are also important sources of a wide range of essential micronutrients. These nutrients include minerals such as iron and zinc, and vitamins such as vitamin A. For the large majority of people in the world, particularly in developing countries, livestock products remain a desired food for nutritional value and taste. However, excessive consumption of animal products can lead to excessive intakes of fat in some countries and social classes leading to health risks.
The growing demand for livestock products results in more intensive production systems that are likely to have undesirable impacts on the environment. For instance, meat production requires a lot more land and water than the production of plant-based foods. Whilst a hectare of land may provide enough rice or potatoes to feed 19 to 22 people over one year, the same amount of land only provide enough lamb or beef to feed one or two people.
This text is a summary of: WHO/FAO
Diet, Nutrition and the prevention of chronic diseases
Section 3.4 Availability and changes in consumption of animal products
Approximately one billion people worldwide rely on fish as their main source of animal protein.Consumption of fish is usually higher in areas that are near the coast, where alternative protein sources are lacking, or where there is a strong preference for fish. On average, fish, crustaceans, and molluscs account for around 15% of the total animal protein intake of the human population.
The average amount of fish and fishery products consumed per person nearly doubled over 40 years, reaching 16 kg per year in 1997. However, the majority of fish stocks are already being fully exploited and as a consequence total production has levelled off since the 1970s. This is cause for concern because fisheries are an important source of the world’s food, employment, and revenue.
Recommendations for daily
intake of fish should take
into account not only its nutritional value, but the future
availability of this food source for human consumption as well.
This availability will depend on the
sustainability of marine
fish stocks and the
proportion of fishery
products used in animal feed.
See "How much is consumed per person?" in our digest on Fisheries
This text is a summary of: WHO/FAO
Diet, Nutrition and the prevention of chronic diseases
Section 3.5 Availability and consumption of fish
A diet high in fruits and vegetables is recommended for a good health, yet currently only a small minority of the world’s population eats an adequate amount.
Between 1970 and 2000, the average worldwide consumption of vegetables increased from 60 kg to over 100 kg per person, but trends vary between countries and regions. A low consumption of fruits and vegetables is a persistent phenomenon in many regions of the developing world, especially in Africa.
In urban areas, people tend to be further away from primary food production which may reduce their access to fresh fruit and vegetables. In this situation the poor may find it especially hard to obtain fruits and vegetables whilst people with higher incomes may have better access to a more diverse and nutritious diet.
This text is a summary of: WHO/FAO
Diet, Nutrition and the prevention of chronic diseases
Section 3.6 Availability and consumption of fruits and vegetables
The world’s agricultural production is growing. However, this growth has slowed in recent years, raising fears that the world may not be capable of growing enough food to ensure that future populations are adequately fed.
The slowdown has occurred not because of shortages of land or water but rather because demand for agricultural products has also slowed. This is mainly due to the fact that the world’s population is growing more slowly and that a high share of the population is too poor to have significant purchasing power.
In developing countries, demand (especially for animal products) is expected to grow faster than production and there will be a need for imports. Extending cultivated land area, and increasing land productivity (possibly by creating irrigation systems) may help increase crop yields and satisfy demand.
Between now and 2030 the average daily energy intake per person is expected to increase by 100 kilocalories in developing countries. Diets previously based on cereal, roots and tubers will increasingly be replaced by diets that are rich in meat, dairy-products and oil. Average consumption of oil crops is expected to rise more rapidly than that of cereals and average consumption of animal products could increase by 44% over the same period.
By 2030, the increase in consumption of fishery products is expected to be more and more limited by environmental factors. Currently, the rapid growth of the aquaculture sector is compensating for the slowdown in marine fish catches.
This text is a summary of: WHO/FAO
Diet, Nutrition and the prevention of chronic diseases
Section 3.7 Future trends in demand, food availability and consumption
Changes in diets are needed to cope with the burgeoning epidemic of chronic diseases. All sectors in the food chain, from "farm to table", will need to be involved in meeting this challenge.
Recommended actions include:
This text is a summary of: WHO/FAO
Diet, Nutrition and the prevention of chronic diseases
Section 3.8 Conclusions
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