We use nationally representative English data to examine regional variations in body mass index (BMI) and waist circumference (WC), and to explore their underlying sources. Beyond our “at the mean” analysis, Shapley decomposition combined with unconditional quantile regression analysis allow us to explore the relative contribution of small-area level proxies of the obesogenic environment as opposed to our set of individual-level characteristics, across the whole adiposity distribution. We find that the regional BMI differences, that are more evident towards the right tails of its distribution, are fully accounted for by the neighbourhood obesogenic environment. The latter exerts an independent contribution to excess adiposity over and above the potential mediating role of individual-level lifestyle and socio-economic position (SEP). Overall, the relative contribution of demographics (age and gender) becomes less evident moving to higher quantiles of the BMI distribution, while that of obesogenic environment, individual-level lifestyle and SEP measures becoming more relevant. The neighbourhood obesogenic environment is also much more relevant in the tails of the WC distribution. The role of the obesogenic environment on excess adiposity is more pronounced for women than men. Overall, our results highlight that policies that aim to tackle excess adiposity should address both people and places.