Nudging or ‘choice architecture’ refers to strategic changes in the environment that are anticipated to alter people’s behaviour in a predictable way, without forbidding any options or significantly changing their economic incentives. Nudging strategies may be used to promote healthy eating behaviour. However, to date, the scientific evidence has not been systematically reviewed to enable practitioners and policymakers to implement, or argue for the implementation of, specific measures to support nudging strategies. This systematic review investigated the effect of positional changes of food placement on food choice. In total, seven scientific databases were searched using relevant keywords to identify interventions that manipulated food position (proximity or order) to generate a change in food selection, sales or consumption, among normal-weight or overweight individuals across any age group. From 2576 identified articles, fifteen articles comprising eighteen studies met our inclusion criteria. This review has identified that manipulation of food product order or proximity can influence food choice. Such approaches offer promise in terms of impacting on consumer behaviour. However, there is a need for high-quality studies that quantify the magnitude of positional effects on food choice in conjunction with measuring the impact on food intake, particularly in the longer term. Future studies should use outcome measures such as change in grams of food consumed or energy intake to quantify the impact on dietary intake and potential impacts on nutrition-related health. Research is also needed to evaluate potential compensatory behaviours secondary to such interventions.

Aim: Negative body image increases the risk of engaging in unhealthy dieting and disordered eating patterns. This review evaluated the impact of habitual social media engagement or exposure to image‐related content on body image and food choices in healthy young adults (18‐30 years).Methods: A systematic search of six databases of observational literature published 2005‐2019, was conducted (PROSPERO Registration No. CRD42016036588). Inclusion criteria were: studies reporting social media engagement (posting, liking, commenting) or exposure to image‐related content in healthy young adults. Outcomes were: body image (satisfaction or dissatisfaction) and food choices (healthy eating, dieting/restricting, overeating/binging). Two authors independently screened, coded and evaluated studies for methodological quality.Results: Thirty studies were identified (n = 11 125 participants). Quantitative analysis (n = 26) identified social media engagement or exposure to image‐related content was associated with higher body dissatisfaction, dieting/restricting food, overeating, and choosing healthy foods. Qualitative analysis (n = 4) identified five themes: (i) social media encourages comparison between users, (ii) comparisons heighten feelings about the body, (iii) young adults modify their appearance to portray a perceived ideal image, (iv) young adults are aware of social media's impact on body image and food choices, however, (v) external validation via social media is pursued. Most studies (n = 17) controlled for some confounding variables (age, gender, BMI, ethnicity).Conclusions: Social media engagement or exposure to image‐related content may negatively impact body image and food choice in some healthy young adults. Health professionals designing social media campaigns for young adults should consider image‐related content, to not heighten body dissatisfaction.

Social media has been widely adopted by young adults, consequently health researchers are looking for ways to leverage this engagement with social media for the delivery of interventions and health promotion campaigns. Weight gain and sub-optimal dietary choices are common in young adults, and social media may be a potential tool to facilitate and support healthier choices. We conducted a mixed-methods systematic review of studies examining social media use for nutrition-related outcomes in young adults. Seven databases [EBscohost, ERIC, ProQuest Central, PubMed, Ovid, Scopus, and Emerald] were systematically searched; 1225 abstracts were screened, and 47 full-text articles were assessed for eligibility. Study designs included both quantitative, such as experimental and observational studies, and qualitative, such as focus groups and interviews, approaches. Quality was assessed using the Mixed Methods Appraisal Tool. Quantitative and qualitative results were examined separately, and then synthesized. Twenty-one studies were included although their use of social media was highly variable. The main purpose of social media was to provide information and social support to participants. In the nine randomized controlled trials, social media was used as one aspect of a multi-faceted intervention. Interventions had a positive statistically significant impact on nutritional outcomes in 1/9 trials. Engagement with the social media component of interventions varied, from 3 to 69%. Young adults appear to be open to receiving healthy eating and recipe tips through social media, however, they are reluctant to share personal weight-related information on their online social networks. Information-dissemination is now an acceptable use of social media by young adults. Using social media effectively for social support, either via private groups or public pages, requires careful evaluation as its effectiveness is yet to be demonstrated in experimental designs. Concerns about public social media use may be a contributing factor to poor engagement with social media in research intervention studies aimed at influencing weight. Future research should consider how to best engage with young adults using social media, how to more effectively use social media to support young adults and to facilitate social and peer-to-peer support in making healthier choices.