The impact of food packaging on measured food intake: A systematic review of experimental, field and naturalistic studies.

Chronic, excess energy intake contributes to overweight and obesity. Solutions are needed to guide consumers towards portion control, especially for high energy density (HED), palatable foods. Food packaging, a key element of the eating environment, offers a potential solution. To investigate whether packaging design influences measured food intake, a systematic search was undertaken in four electronic databases (Ovid Medline; Ovid PsycInfo; Ovid Embase and Web of Science) across the previous decade. This process yielded 1671 discrete papers, of which 23 articles containing 40 relevant studies were retrieved. Most (n = 36) of the manipulated packaging features influenced consumption quantity with the largest effect sizes observed for packaging which guided consumers either by on-pack cues or structural features. For example, images on the front of the pack, packaging size, as well as partitioning and resealability all helped to reduce food intake. However, individual differences and attentional focus mediate packaging effects. Overall, packaging features can help to limit intake of HED foods and increase intake of nutrient-dense foods (e.g., carrots). Future studies on packaging for portion control (downsizing) might benefit from long term, randomised control trials to test effects outside of the laboratory context and applied to everyday consumer usage.