Malnutrition is manifested in various degrees of both underweight and overweight, with large differences and rapid changes in their prevalence and severity. This paper introduces a new approach to characterizing the distribution of a population’s nutritional status, to help analyze changes in that distribution over time and across countries. Our method draws on the poverty literature to construct Foster-Greer-Thorbecke measures for the incidence and severity of under- and overweight, based on deviations in either direction from the median of a healthy population. We apply this median-based measure to the nutritional status of over 400,000 preschool children, as measured in 130 DHS surveys covering 53 countries over a period from 1986 to 2006. Unlike conventional threshold-based methods, the new approach counts changes in every child’s bodyweight. We find that this offers a more sensitive measure of differences across countries and changes over time, showing in particular that children’s bodyweights are closely linked to local agricultural output and gender equality as well as real GDP per capita.