The effect of the labelled serving size on consumption: A systematic review

Guidance for food consumption and portion control plays an important role in the global management of overweight and obesity. Carefully conceptualised serving size labelling can contribute to this guidance. However, little is known about the relationship between the information that is provided regarding serving sizes on food packages and levels of actual food consumption. The aim of this systematic review was to investigate how serving size information on food packages influences food consumption. We conducted a systematic review of the evidence published between 1980 and March 2018. Two reviewers screened titles and abstracts for relevance and assessed relevant articles for eligibility in full-text. Five studies were considered eligible for the systematic review. In three of the included studies, changes in serving size labelling resulted in positive health implications for consumers, whereby less discretionary foods were consumed, if serving sizes were smaller or if serving size information was provided alongside contextual information referring to the entire package. One study did not find significant differences between the conditions they tested and one study suggested a potentially negative impact, if the serving size was reduced. The influence of labelled serving size on consumption of non-discretionary foods remains unclear, which is partially due to the absence of studies specifically focusing on non-discretionary food groups. Studies that investigate the impact of serving size labels within the home environment and across a broad demographic cross-section are required.