FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS	ESN: FAO/WHO/UNU EPR/81/Inf. 10 September 1981
	WORLD HEALTH ORGANIZATION
	THE UNITED NATIONS UNIVERSITY

INFORMATION PAPER NO. 10

Joint FAO/WHO/UNU. Expert Consultation on Energy and Protein Requirements

Rome, 5 to 17 October 1981

SOME ISSUES IN THE APPLICATION OF ENERGY REQUIREMENT

ESTIMATES

by

G.H. Beaton
University of Toronto
Ontario, Canada

In the course of conducting a comparative study of the FAO and World Bank (Reutlinger and Alderman) approaches to describing the magnitude of nutritional problems, ⁽¹⁾ certain ambiguities of the 1971 FAO/WHO report and of its interpretation became apparent. Insofar as they may represent issue for many persons wishing to use the report for population studies, the salient points are summarized; not in particular order of importance or priority.

1. Variability of Requirements

It is recognized and generally accerted that among seemingly comparable individuals there is considerable variation in “usual” requirement (i.e. requirement persisting non reasonable periods of time). This may be seen in two dimensions: (i) the variation explained by category of activity, (ii) inherent biological variability (remaining after adjustment for body weight). On the former, the FAO/WHO report provides suggestions about adjustment of group average energy requirement. (But provides very limited guidance with regards to the fitting of these descriptions to actual populations). On the latter point, the report is relatively silent.

The absence of discussion, in quantitative terms of the likely variabili of requirement is a serious short coming in application of the report.

(1) Numerical descriptions of the Nutrition Problem: An Analytical Comparison of FAO and World Bank Approaches. G.H. Beaton Report to FAO, March, 1981

2. Energy Requirement for What ?

As noted above, the 1971 report described energy requirement for various levels of activity in adults. It did not do this for children. It did not provide guidance in the effective translation of the descriptors to population.

Subsequent to publication of the report some of the participants published a note pointing out the fact that, considered in terms of maintenance of energy balance and population survival, we must recognize that almost all populations have met energy requirements - apparently at intakes well below the levels suggested by the FAO/WHO committee.

Clearly adaptations accur. The report was relatively silent on this matter and particularly on the question of the socio-physiologic significance of the adaptations.

This apparent contradiction between theory and experience has challenged the credibility of the 1971 report. For persons wishing to use the report it has left many serious questions, and considerable conflict of interpretation. These revolve around the central question of “energy requirement for what?” - and the possible difference in answers if one were interested in assessing the magnitude of certain inadequacies vs. attempting to plan future food needs. This issue was central in the UNU workshop on the use of requirement estimates.

A relative issue is the definition and interpretation of “maintenance energy requirement” (suggested in 1971 to be approximately 1.5 BMR. In theory it is clear what this is intended to mean. In practice it is not clear what judgement should be applied when one sees energy intakes at this level. Can we expect population groups to survive in “health” at this level of intake or is this minimal survival need rather than minimum physiologic need or maintenance requirement ?

(See also report of UNU meeting and background paper by Beaton, No. 24).

It would seem essential that the FAO/WHO/UNU 1981 committee address, and offer best judgements on, energy requirement estimates for various levels of social adaptations, i.e. normative definitions.

3. Relationship between per capita Food Disappearance and per capita Weighted Intake

The data base available to planners in developing countries is often per capita disappearance figures. Clearly, these figures are higher than actual intake since there must be some losses. The per capita figures are ajusted to losses to the retail level. FAO, on recommentation from an earlier committee, further adjusts these for losses within the household. Interestingly, this has been done by increasing requirement estimates by 10% (rather than discounting disappearance figures). To users this has caused serious confusion - published FAO per capita requirement estimates are actually 10% higher than those suggested by the 1971 committee.

Two questions arise :

1. What is a recommendable assumption for FAO to make about household losses of food in developing countries, (i.e. magnitude of loss between purchase and consumption) ?
2. How should FAO report this loss in presenting country statistics - reduce the per capita disappearance or increase per capita requirement ?

4. Intrahousehold distribution / Household Requirement

Commonly the lowest level of disaggregation of population data is the household unit (e.g. as in household food purchase or food expenditure studies). Conversely requirements are expressed in terms of individuals. An alternate approach, in use for many years has been to describe requirements / analyse intakes in terms of “consumer units” assigning weights to various categories of individuals in proportion to their energy requirements in relation to that of reference man.

While these approaches were successful when only the average requirement was of interest, there is a serious conceptual problem in that :

1. intrahousehold distribution of intake must be assured to be equitable and proportional to requirement.
2. it is not all clear how variability of requirement for a household or for a consumer unit should be estimated from estimates of variability of individual requirement.

It is expected that guidance from the committee on either or both of these issues would be appreciated by users.

5. BMR

At present, at the suggestion of the 1971 committee, FAO is using 1.5 BMR as a description of maintenance energy requirement. There have been questions raise about the appropriate BMR to be used in such a calculation. These questions include such conceptual issues as :

1. does the calculation of BMR from body weight give adequate recognition to diferences in body composition between the reference population and the population in the developing country ?
2. if country specific data are available should these be used or do they reflect undesirable physiological adaptations to low energy intakes.

As a reminder of the importance of even seemingly small changes in requirement estimates, a change of 10% in requirement estimate could result in a 2-fold change in the estimated magnitude of the nutrition problem (estimated prevalence of inadequate intakes) by either the FAO or World Bank approaches. All comment/planning models are very sensitive to changes in the requirement estimate, - or to differences in the interpretation of the 1971 report as read by others. This is a matter of great importance to planners - and a sources of much ill-directed criticism of the 1971 report (“It couldn't be correct” - they way some have interpreted it).