No / Globally supermarkets have been seen as a remedy to the problems of poor diets in deprived neighbourhoods where access to healthy foodstuffs has been limited. This study seeks to quantify the consequences of one such United Kingdom intervention, in Seacroft, Leeds. Where previous work often focused on fruit and vegetables, this paper presents evidence on all food and drink consumed before, and after, the new opening. It is shown that utilising large format retailers can also bring significant negative consequences for already unhealthy diets, exactly the opposite of what policy makers set out to achieve. Suggestion is therefore made that policymakers consider using price, or education, interventions rather than promoting large shops, which, while stocking cheap healthy food also offer shoppers the unhealthy produce they like at low prices.