It is commonly stated that 'snack' foods provide 'empty calories' and, therefore elevate energy intake whilst providing insignificant quantities of other nutrients. The data presented in the present review suggest that foods which contribute to the pattern of 'snacking' contribute significantly to the nutrient quality of the diet. Those who 'snack' frequently tend to eat more food in general. Part of the difficulty in identifying the nutritional implications of 'snacking' is related to the definitions of 'meals' and 'snacks' and subsequent categorization of individual patterns. The physiological definitions typically relating to energy content or the time of eating do not necessarily coincide with colloquial, cultural or individual perceptions of what constitutes a 'meal' or 'snack'. Clearly, a more consistent approach would facilitate interpretation of the literature and enable more effective health education messages about 'snacking' to be delivered.