The purpose of the expert consultations on human energy requirements convened by FAO, WHO and, more recently, UNU is to advise the Directors-General on scientific issues related to food energy, including requirements, so that appropriate recommendations for action can be formulated. It is hence important that during the process of determining energy requirements the question of "requirements for what?" be constantly borne in mind. While biological scientists are generally concerned with the physiological basis of estimating requirements, it is also necessary to be aware of the practical applications of these recommendations for estimating the energy requirements and food needs of populations worldwide.
The principal objective of expert consultations on human energy requirements is to provide international agencies and their member countries with the necessary tools for addressing practical questions, such as assessing the adequacy of food supplies and the numbers of people who do not attain energy adequacy, drawing up targets for food production and informing national food and nutrition policy and planning. The recommendations and guidelines that result from these consultations will serve to enable governments and organizations to plan, monitor and evaluate nutrition programmes and policies better. They will also help Member Nations to develop estimates of requirements appropriate for local conditions and for direct application in their countries. It is important to remember that while developed countries are able to constitute their own committees of experts who can make recommendations on energy and nutrient requirements for their populations, the majority of humanity in the developing world relies largely on UN agencies such as FAO. Hence, the development of pragmatic recommendations by expert committees convened by UN agencies, which are based on sound scientific evidence and have practical relevance to the conditions prevailing in the developing world, is paramount.
The entire process leading up to the convening of an expert group and the resulting consultation is highly formalized and follows a number of required protocols. For the first time, FAO adopted a two-stage process, which started with convening working groups in those areas where it believed that new scientific knowledge existed that might influence the current recommendations for energy needs. The second stage of the process was the expert consultation itself. The rationale behind convening the working groups was that many of the scientific questions could be dealt with by experts in the areas concerned, even though the participation of those experts at the consultation per se was uncertain owing to the need to provide a globally representative consultative panel. Working groups would also facilitate discussions, as any contentious issues could be debated and settled before the expert meeting, which would benefit from the results of such discussions. Accordingly, working groups met from 27 June to 5 July 2001 at FAO headquarters in Rome, several months before the expert meeting in October 2001. Three of the working groups focused primarily on energy requirements throughout the life cycle and related to two important sub-populations - infants and children, and pregnant and lactating women - for which substantial scientific advances had been made. These working groups were on: 1) energy (and protein) requirements of infants and preschool children; 2) energy (and protein) requirements of pregnancy and lactation; and 3) analytical issues in food energy and composition: energy in food labelling, including regulatory and trade issues, which looked at food energy values. An additional working group was constituted to provide documentation on methodologies for energy balance and energy requirements, but it was felt that - given the nature of the task - there was no need for this group to meet, although their background documents were available to the expert consultation. The chairpersons of all the working groups on energy were invited to the expert consultation to present a summary of the deliberations and recommendations of their groups and to advise the experts. Background papers were commissioned, peer-reviewed and made available to both the pre-consultation working groups and the experts who met for the consultation. The entire process of pre-consultation activities and the consultation itself went smoothly, despite a few hitches that were largely the result of the unhappy events of 11 September 2001, which prevented some of the invited experts from coming to Rome to join the consultative process. Lists of the participants in the various working group sessions, and those invited as experts to the consultation are included as Annex 1 of this report. Annex 2 provides details of the authors and reviewers of the background documents, which are expected to be published shortly as a supplement to the journal Public Health Nutrition. The wide availability of this publication as a peer-reviewed journal supplement is expected to provide the academic community with an opportunity to examine the collated evidence base that informed the expert panel and influenced their latest recommendations.
As part of the second stage of the process, the members of the expert consultation met in FAO headquarters in Rome from 17 to 21 October 2001. The meeting was chaired by Dr E. Kennedy, with Dr B. Torun serving as rapporteur. The following are the specific tasks outlined in the charge given to this expert consultation on human energy requirements:
1. To review the background documents on the state of the art of the scientific literature in this area of work, assembling the best evidence on the topic and using, where appropriate, the summary, advice and recommendations arising from the deliberations of the working groups that had met earlier in the year.
2. To deliberate on and arrive at recommendations for energy requirements throughout the life cycle, while clearly outlining the approaches used to estimate requirements that may be of benefit to users. This included taking into account physiological states such as growth, pregnancy and lactation and, where relevant, pathological conditions and the additional needs during infections. The recommendations were expected to be reached by consensus, and where differences persisted the reasons for those differences were to be clearly outlined, with all sides presented and appropriately reflected in the report of the expert consultation.
3. To examine the feasibility of arriving at minimum requirements that may be of use in estimating the numbers of individuals in populations who are unable to meet energy adequacy.
4. To comment on the consequences of deficit and excess of energy, and to recommend ways by which the health, social and economic consequences of these can be minimized or avoided.
5. To highlight the main changes to the recommendations of the 1985 report, with particular emphasis on those aspects of the new recommendations that have a significant impact on the way in which nutritional adequacy of population groups is assessed by those involved in policy, planning or analysis of the nutritional status of populations.
6. To suggest areas where further research is needed, either to deal with gaps in the knowledge related to energy requirements in specific groups or situations, or to facilitate the collection of normative data that will aid the process of arriving at future recommendations for energy requirements.
It was the sincere desire of the FAO Secretariat to ensure that the report of the expert consultation on human energy requirements be available within the shortest possible period after the experts met in Rome. The two-year gap before the interim report was available as a downloadable file on the FAO Web site, and a further period before it was available in hard copy were due to a series of post-consultation activities that were deemed essential before the release of the final report. Many of these post-consultation activities were in response to, and out of respect for, the experts who recommended a number of important pieces of work to be followed-up and completed for inclusion in the report.
An important recommendation of the expert group was to update and review the predictive equations for estimating basal metabolic rate (BMR) and to incorporate the updated equations into the new recommendations. These activities proved to be time-consuming, as they involved updating the global database on BMRs that was originally obtained for the 1985 report, reanalysing it with particular emphasis on looking at the influence of methodological biases and ethnic variations, and developing new BMR predictive equations with better predictive performance for international use (Annex 3). The reanalysis was followed by an exercise to test the validity of the new equations, and a further consultation with a sub-group of the expert panel for their final decision. However, after this long exercise the experts concluded that the international equations hitherto used continued to have enhanced precision and robustness. Following reanalysis of the global database, the recommendation to use a seamless single predictive BMR equation was not considered practical, and hence the expert consultation was not persuaded to replace the international equations provided in the 1985 report. These predictive equations have been widely used and are popular with the scientific community and nutritional planners, and the present report’s recommendation is to continue using them.
One of the other recommendations that arose from the deliberations of the working group on analytical issues in food energy and composition, which was subsequently endorsed by the experts, was to convene a meeting to deliberate on food energy values. The objective was to ensure harmony between the expected adoption of new energy requirement values from this consultation, which are based solely on energy expenditure measurements or estimates, and energy requirements based on food intake measurements alone. FAO thus convened a Technical Workshop on Food Energy - Methods of Analysis and Conversion Factors, which was held in Rome from 3 to 6 December 2002. The report of this workshop was published as FAO Food and Nutrition Paper No. 77 in 2003, which complements the present report.
As part of the post-consultation activities in preparation for the release of the expert report, it was decided to produce an updated, Windows-compatible and user-friendly software application for the purpose of calculating population energy requirements and food needs. After the 1981 joint expert consultation report was released (WHO, 1985), FAO sponsored the development of a manual and software package (James and Schofield, 1990), recognizing that less attention had hitherto been paid to the matter of how to apply the requirements to practical food and nutrition planning. The success of this 1990 user’s manual, which was sponsored by FAO and published by Oxford University Press, was constrained because it was a priced publication that was available separately from the 1985 joint expert report. For the 2001 consultation, it was decided to make the new software widely and readily available by releasing it alongside the report. FAO therefore had to find an organization that would assist us in developing such a product to be released at the same time as the expert report in 2004. Early discussions were conducted with the United States Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, with the objective of developing the software and making it available as a downloadable version alongside CDC’s popular EpiNut software. However, CDC was unable to collaborate in this venture, so other partners had to be sought. The Division of Nutrition, Institute of Population Health and Clinical Research at Bangalore, India and its Dean, Dr A. Kurpad, identified Jenesys Technologies, a software applications firm in India, which collaborated alongside the institute in the development of the software package and accompanying manual (Annex 4). This is now available on CD-ROM. For the first time, the software package is being issued together with the expert report in order to ensure that those interested in the report’s recommendations have the means to investigate and ensure their practical applicability, as well as to benefit from the two outputs’ complementarity. The user’s manual and software application for calculating population energy requirements and food needs thus represent a further milestone in FAO’s continued involvement in both the theoretical and the practical issues related to human energy requirements.
This expert consultation was convened nearly two decades after the last expert group met to deliberate on energy and protein requirements in 1981. In the interim, the International Dietary Energy Consultancy Group (IDECG), sponsored jointly by UNU and the International Union of Nutritional Sciences (IUNS), filled the lacuna by convening meetings to discuss important developments in this area. The IDECG meeting in London in 1994 on Energy and Protein Requirements (whose proceedings were published in European Journal of Clinical Nutrition Vol. 50, Supplement 1 in February 1996) was a seminal meeting that provided much of the preparatory background for this expert consultation. We would like to acknowledge and pay our tribute to the late, Dr Beat Schurch who, as Executive Secretary of IDECG, was the quiet engine behind this invaluable contribution to the advancement and dissemination of nutrition knowledge. FAO and WHO benefited greatly from IDECG’s work and publications, in particular its review of human energy and protein requirements in 1994. While FAO was organizing the 2001 expert consultation, Beat Schurch knew that he was sick but planned to attend both the consultation and the working groups that preceeded it. Unfortunately, his illness progressed more quickly than had been anticipated, and he had to decline the invitation. He approached his illness and its culmination with the same equanimity with which he approached most matters and wished the group well. His contribution and friendship will be sorely missed.
Prakash Shetty
Chief
Nutrition Planning,
Assessment & Evaluation Service (ESNA)
Food & Nutrition
Division
