This review discusses the role that dietary composition and energy density play in the control of eating behaviour. The effect of dietary manipulations of fat and carbohydrate on energy intake remains controversial. We suggest this to be largely a consequence of different study designs. When low-fat foods are included in the diet and thus only some items manipulated subsequent food choice commonly ensures compensation and energy intake remains constant. However, when all items are manipulated and macronutrient composition fixed, an alteration in the energy density results in a parallel change in energy intake and there is no energy compensation. In addition, we hypothesise that hyperphagia on high-fat diets is a consequence of a high energy density rather than fat content per se. Independent of fat content, low energy dense diets generate greater satiety than high energy dense diets, suggesting that an important regulatory signal may be the weight or volume of food consumed. Epidemiological studies confirm that energy intake increases with energy density and thus weight loss may be best achieved on a low energy dense diet. Although the use of low-fat items may not reduce intake during covert manipulation, it may be successful during periods of deliberate dieting, providing that food-substitutions are not counter-balanced by other high density items.