Since 1949, the Food and Agriculture Organization of the United Nations (FAO) and, since the early 1950s, the World Health Organization (WHO) have convened groups of experts to evaluate current scientific knowledge in order to define the energy requirements of humans and propose dietary energy recommendations for populations. The purpose of this information is to assist FAO and WHO in implementing their programmes. The United Nations University (UNU) became part of this joint initiative in 1981. The reports of these expert meetings (see the list of References at the end of this chapter) have become important guidelines on energy in human nutrition for academic scientists, nutritionists, physicians and other health workers, as well as for planners and policy-makers in both the agriculture and health sectors throughout the world.
New scientific knowledge generated in the 20 years since the last expert consultation was held prompted FAO, WHO and UNU to assemble a new expert consultation to make recommendations for energy requirements of populations throughout the life cycle (WHO, 1985). This consultation took place from 17 to 24 October 2001 at FAO headquarters in Rome. Its mandate was to revise and update the conclusions and recommendations of the preceding consultation, which was convened in 1981 and whose report was published in 1985. In preparation for the forthcoming expert consultation, well-known scientists with demonstrated expertise in this area of work were asked to examine and write background papers on various topics that required revision and updating. Several of the authors and other leading scientists constituted working groups that met in Rome in June 2001 to discuss and analyse critically the contents of the background papers, which were subsequently modified following the working group suggestions. The modified papers, the working groups conclusions and other relevant documents were provided to all members of the expert consultation for analysis and consideration in their deliberations.
Dr Eileen Kennedy was elected to chair this expert consultation, and Dr Benjamin Torun to be the rapporteur. Several conclusions and recommendations were the immediate results, while a number of topics were identified as requiring further research and analysis before the experts could finalize their recommendations. The rapporteur and other members of the consultation were given the task of pursuing the pending issues with assistance from the FAO Secretariat, and additional working papers were commissioned. This laborious task went on until the end of 2003, when almost all questions had been answered and gaps filled and the rapporteur was able to prepare the final draft for examination and approval by the other experts from the consultation. This report is the final result of those efforts.
Although the basic principles set forth in previous expert meetings have withstood the test of time, several modifications are proposed in this report. Members of the expert consultation and participants in the working groups recognize and accept the responsibility for proposing these modifications, and for the implications that they will have on health, agriculture, the food industry, economic planning, international aid and social programmes related to food and nutrition. It is their belief that the conclusions and recommendations in this report are well grounded, given the current state of the best scientific knowledge. A critical appraisal of their application will be the final proof of their accuracy, applicability and appropriateness.
The new concepts and recommendations set forth in this report include:
calculation of energy requirements for all ages, based on measurements and estimates of total daily energy expenditure and on energy needs for growth, pregnancy and lactation;
in the light of new data, modification of the requirements and dietary energy recommendations for infants and for older children and adolescents, in order to correct previous overestimations for the former and underestimations for the latter;
proposals for differentiating the requirements for populations with lifestyles that involve different levels of habitual physical activity, starting as early as six years of age;
reassessment of energy requirements for adults, based on energy expenditure estimates expressed as multiples of basal metabolic rates;
classification of physical activity levels based on the degree of habitual activity that is consistent with long-term good health and maintenance of a healthy body weight;
recommendations for physical activity for children and adults to maintain fitness and health and to reduce the risk of developing obesity and co-morbid diseases associated with a sedentary lifestyle;
an experimental approach for factorial estimates of energy needs during pregnancy and lactation;
distribution in the two last trimesters of pregnancy of the recommendations for additional dietary energy needs.
This report is briefer and less detailed than the reports of previous expert meetings and consultations. The commissioned background papers, which will be published in a peer-reviewed journal, complement the report with details on the sources, analysis and interpretation of the scientific information. In addition to a printed version, the report will be placed on the Internet for wider access and faster diffusion.
This report is not meant merely to describe the energy expenditures and requirements of population groups. It intends to be prescriptive, in order to support and maintain health and good nutrition. The recommendations, however, are meant for well-nourished and healthy populations, as the correction of malnutrition - either deficit or excess - involves different energy requirements and dietary recommendations. The report is not meant to be prescriptive for individual subjects, some of whom may be at either extreme of a normal distribution. Although estimates of requirements are derived from measurements of individuals with specific characteristics such as age, gender, body size, presumed body composition and physical activity, the data have been pooled to give the average energy requirements of groups or classes of individuals who have similar characteristics, but on whom measurements have not been made. Consequently, application of these results to any one individual for clinical or other purposes may lead to errors of diagnosis and improper management.
A science-based definition of human energy requirements is crucial for the control and prevention of undernutrition due to insufficient intake of food energy, which remains a major problem for many countries. It is also essential to efforts to curb the excessive intake of food energy that is a major determinant of nutrition-related chronic diseases, at present an important cause of worldwide morbidity and mortality among adults.
Insufficient food energy intake is almost always accompanied by a deficient intake of most nutrients. Awareness of the consequences of insufficient energy intakes in children and adults has influenced health and food and agriculture policies around the world. More recently, the consequences of increasing obesity and nutrition-related chronic diseases have also been recognized as major factors for the health, food and agriculture sectors. These problems are increasing globally as a result of changes in diets and lifestyles that are reflected in changing food cultures and physical activity patterns among all segments of society, and not only among affluent groups or in the richest countries. Undernutrition early in life, followed by an inappropriate diet and low physical activity in childhood and adult life increases vulnerability to chronic non-communicable diseases. Low-income groups in urban areas are especially vulnerable to the risk of obesity owing to a positive energy balance. The current increased incidence of overweight and obesity among children and adults in most countries leads to rapidly rising projections of disability and premature death to nutrition-related chronic diseases.
Prevention is the only feasible approach to control the double burden of under- and overnutrition. The cost of treating and managing the ensuing disabilities and diseases imposes an intolerable economic and health burden, especially for poorer countries. As inappropriate dietary intake and lack of physical activity are the main causes of nutritional problems, there is an urgent need for governments, in partnership with all relevant stakeholders, to integrate strategies that promote healthy diets and regular physical activity in all relevant policies and programmes, including those designed to fight undernutrition. Both undernutrition and obesity are preventable, as has been demonstrated by countries with successful programmes. In addition to health promotion, nutrition education and relevant agricultural and food policies, effective food and nutrition programmes must include community action to overcome the environmental, social and economic constraints that limit the improvement of access to food, and to promote better dietary quality and life style practices that encourage a physically active life.
FAO. 1950. Calorie requirements: Report of the Committee on Calorie Requirements. FAO Nutritional Studies No. 5. Rome.
FAO. 1957. Calorie requirements: Report of the Second Committee on Calorie Requirements. FAO Nutritional Studies No. 15. Rome.
FAO/WHO. 1973. Energy and protein requirements: Report of a joint FAO/WHO ad hoc expert committee. FAO Nutrition Meetings Report Series No. 52. WHO Technical Report Series No. 522. Rome and Geneva.
WHO. 1985. Energy and protein requirements: Report of a joint FAO/WHO/UNU expert consultation. WHO Technical Report Series No. 724. Geneva.
 Annex 1 gives the names of
participants in the working groups and expert consultation. Annex 2 lists the
titles and authors of the background documents.|