Summary. Using the nationally representative Survey of Lifestyle, Attitudes and Nutrition in Ireland data set we take several approaches to profile the change in obesity in Ireland over the 2002–2007 period. There is no evidence of either first- or second-order stochastic dominance between the two years. There is evidence that obesity and overweight are relatively more concentrated among males, the old and those with lower educational achievement. Although obesity fell marginally over the period this was due to a change in the shape of the distribution of body mass index rather than a rise in the average level. Finally a semiparametric decomposition of the change in the distribution over time indicates that the change in obesity arose not because of changes in population characteristics but rather in the effect of these characteristics on body mass index.