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In common with each of its predecessors, the present report on energy and protein requirements attempts to move ahead and break new ground, presenting new concepts and identifying fresh issues. Perhaps one of the major changes that characterizes this report, in addition to the new approach to the derivation and description of energy requirements, is the recognition that the requirement estimates really relate more closely to individuals than to populations. This is in almost direct contradiction to the statements found in the introductions to most previous reports. Major practical implications follow from this recognition. In this report the significance of issues of variability and correlation, as well as the biological problems involved in estimating requirements, have been recognized and an attempt has been made to deal with them concurrently.

One of the effects of this change in concepts and of our recognition of new issues in the application of requirements has been the omission of the usual section on application, with its tables of per caput requirements for protein and energy. Instead the present section 11 on issues and approaches to application, has been included. In a way this is an admission of ignorance. To an important extent it is also a plea to users of the report to carry on the work that has been started by the Consultation—to explore the issues of application that have been displayed and to find approaches to application and interpretation that honour both the biological and statistical principles involved.

In this search for meaningful approaches to application, the users will have to deal with an issue that is now central to the discussion of energy needs. In physiological terms, energy requirement may be defined as the level of intake required to match the levels of expenditure (including costs of growth, pregnancy, and lactation). With very good expenditure data and meticulous methodology, the careful investigator may be able to establish that existing intakes of energy are adequate to maintain the status quo. That would be a logical conclusion, but the present Consultation was not satisfied that it would be a meaningful solution, since it challenged the adequacy of the status quo situation in a number of settings. For this reason, the Consultation has made “normative” judgements about levels of activity, growth rates, and body proportions that are deemed to be desirable. Others may challenge the particular judgements that have been offered, but they cannot challenge the concept. If the present judgements are thought to be inappropriate then it is up to the user, or the community of users, to offer more appropriate judgements. No longer can we bypass the question “Requirements for what?”

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