When trying to obtain an estimate of the demand function of households for certain food items, it is often convenient to express the demographic structure (size, age and sex composition) of individual households in terms of so many consumer (e.g. an adult male) equivalents. In many studies such conversions have been made by using adult equivalence scales derived from nutrionists estimates of the consumption requirements of human beings at various ages. However these scales, by their nature, are based on estimates of how much a person of a given age and sex should consume, rather than on how much the same person actually does consume in real life. In an endeavour to overcome this difficulty a method is suggested in this article whereby a scale can be calculated from the observed behaviour of households.