Energy density of snacking episodes and eating behaviour: A systematic review of experimental studies

Snacking episodes can be defined as food and drink that are consumed between mealtimes. Snacking episodes can differ greatly in nutrient and energy content, having the potential to influence diet quality and, in turn, health. This systematic review aimed to understand the impact that the energy density of snacking episodes has on eating behaviour outcomes. Objective outcome measures included ad libitum snack intake and daily energy intake, and subjective measures included self-assessed hunger and satisfaction. Eight databases were searched based on set inclusion and exclusion criteria to identify peer-reviewed experimental studies with adult populations. Across the ten eligible studies, seven assessed hunger, five assessed fullness, one assessed overall satiety, five assessed desire to eat/prospective food consumption, and eight assessed energy intake, ad libitum intake/compensation with respect to the impact of snacking episodes' energy density. The weight of the evidence suggested that the energy density of snacking episodes has little effect on eating behaviour outcomes, with limited evidence suggesting that higher energy density snacking episodes could result in higher satiety levels and influence fullness levels but only at specific time points. Risk of confound was high, including little control over volume and sensory characteristics across studies, particularly those reporting significant effects. Overall, this literature would benefit from using standardised snacking comparisons, to confidently identify the impacts of energy density for snacking episodes on eating behaviour outcomes. Findings could inform future studies that aim to understand the formulation of snacking episode considering energy density, to benefit diet quality whilst maintaining consumer satisfaction. • A systematic review exploring the impact of energy on eating behaviour outcomes. • Little influence of a snacks' energy density on eating behaviour outcomes. • Higher energy could result in higher satiety, but only at specific time points. • High risk of confound across then ten studies included. • The literature would benefit from standardised snacking comparisons.