Although surveys have reported that the fat content of the diet has decreased over past decades, the prevalence of obesity has continued to rise in Europe and North America. This phenomenon, ‘the American paradox’, has been attributed partly to an inability of the reduction in dietary fat to reduce excess body fat, and partly to the over-consumption of low-fat products, which, despite their reduced fat content, have in some cases been accused of maintaining a high energy density due to low fibre and water contents, and a high content of refined carbohydrates. In Denmark, the prevalence of obesity has increased in a period in which national dietary surveys have reported a reduction of more than 10% in dietary fat content. Analysing the Danish situation, it seems unlikely that the occurrence of the American paradox in Denmark is caused by the increased consumption of energy-dense, low-fat foods. Other explanations, e.g. the under-reporting of dietary fat in surveys and the clustering of obesity-promoting lifestyles in subgroups of the population, should be sought.