Background: The prevalence of obesity has nearly doubled in Ireland since 1990 and over half of the population has a large waist circumference (WC). No food-based, dietary guidelines exist in Ireland for a reduction in the prevalence of body fat or obesity. Objective: To examine the association between daily food intake and categories of body mass index and WC for the development of dietary guidelines to combat obesity. Design: Cross-sectional study of a random representative sample of 1379 adults aged 18-64 years from Northern Ireland and the Republic of Ireland. Measurements: Weight, height and WC were measured according to standard procedures. Diet was assessed using a 7-day food diary from which 28 food groups were generated and entered into logistic regression analysis. Results: Higher mean daily consumption of most of the 28 food groups was associated with an increased likelihood of being classified as obese or at waist action level 2, compared to normal weight and normal WC. The strongest associations were found for savoury snacks, butter and full fat spreads. Contrary to popular opinion, not one individual food group but rather a combination of many foods was associated with excess adiposity. Conclusions: Body mass index and WC in adults are strongly influenced by the amount of food consumed. Public health policies for a reduction in body fat and obesity may be more effective if the emphasis is placed on a reduction of food and beverages consumed as opposed to the traditional dietary recommendations for macronutrients.