Abstract
Studies of dietary intake are based on the assumption that the methods used are valid and provide measures of habitual intake. It is only recently that data from whole-body calorimetry and doubly-labelled water studies of energy expenditure have yielded insights into the validity and interpretation of energy intake data. In this paper we review the evidence from these and other studies that have led to researchers' current level of understanding of how best to analyse and interpret reported energy intake data. We also discuss what we consider should be the focus of future research needed to refine experimental protocols and evaluate data.