A critique of the effects of snacking on body weight status.

Increasingly Western populations appear to be moving away from the 'gorging' to the 'nibbling' pattern of eating, probably as a direct result of the increased availability of snack foods and snacks. There have been many individual suggestions for the definition of a 'snack', each one based on different parameters of measurement (Rotenburg, 1981; Bernstein et al, 1981; De Castro, 1993). However, no one definition has been universally accepted in the scientific literature due to the problems inherent in individual perception of what constitutes a 'snack' as opposed to a 'meal'. For the purposes of this review, however, a snack is defined as 'any food taken outwith a regular mealtime (namely breakfast, lunch and dinner) or snack item taken in place of such meal.' Snacking is commonly regarded by the general public as predisposing to overweight and obesity, believing that it is more beneficial to adhere to an eating pattern of three meals a day. Thus, in this context, many weight reduction programmes include avoidance of snacks, reducing the frequency of eating occasions to two to three times a day. Indeed one hypothesis, the Booth hypothesis (Booth, 1988), suggests that this growing trend for snacking is a major factor in the aetiology of obesity. However, there is evidence to suggest that snacking, per se, may not necessarily predispose to overweight and that those individuals who snack throughout the day may have positive advantages, in terms of body weight control, over those conforming to a rigid pattern of three meals a day. This paper reviews the literature in the area of eating frequency with respect to energy balance and body weight control and suggests some directions for further research.