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 [Correction added on 14 October 2019, after first online publication: The affiliations of authors Siân McLean and Linda Brennan have been corrected].

Health promoters have been unable to reach and engage people on social media (SM) to the extent that food industry brands and lifestyle personalities have. The objective of this study was to identify the SM post strategies associated with higher engagement in nutrition and food-related posts using a retrospective content analysis. The six most engaging posts from both Facebook and Instagram’s 10 most successful nutrition and food-related accounts were analysed across four fields. Subjective and objective post strategies were coded on 736 posts, and associations with engagement were explored using the Least Absolute Shrinkage and Selection Operator (LASSO). Lifestyle personalities recorded the highest absolute engagement, while health promoters recorded the highest engagement relative to follower count. Strategies associated with higher Facebook engagement included using hashtags and prompting engagement through announcements, while on Instagram, higher engagement was associated with higher caption counts, providing health information links, prompting engagement through strategies that require an action, and using humorous strategies. Strategies associated with lower Instagram engagement included reposted content, general encouragement to eat strategies, encouragement to exercise strategies, not inducing any emotion/hedonic sensations, and providing a negative tone. Health promoters should adapt SM posts to the different SM platforms and utilise strategies associated with higher engagement to engage with their audience on SM.

Background Social media–delivered health promotion has demonstrated limited uptake and effectiveness among young adults. Understanding how young adults interact with existing social media platforms for health might provide insight for future health promotion interventions. Objective The aim of this study is to describe how young adults interact with different social media platforms for health and health information. Methods We used a web-based conversation methodology to collect data from 165 young adults aged 18 to 24 years. Participants participated in an extended conversation with moderators and other participants about health and social media. They were prompted to discuss how they find health information, how they use different social media platforms, and how they evaluate the trustworthiness of information. A thematic qualitative analysis was applied to the data. Results Young adults spent a lot of time scrolling through Facebook newsfeeds, which often resulted in seeing health-related content either from their friends, news sources, or advertisements. Some actively sought out information about specific health areas by joining groups or following relevant pages. YouTube was considered a useful source for learning about everything and was often the go-to when searching for information or advice (after Google). Young adults found the video format easy to learn from. They stated that they could identify accurate YouTube health content by cross-checking multiple videos, by feeling that the presenter was real and relatable, or just through instinctively judging a video’s credibility. Instagram was a source of inspiration for health and wellness from those whose lives were dedicated to healthy lifestyles and fitness. Twitter, Tumblr, and Snapchat were rarely used for health information. Conclusions Most young adults obtain health information from social media, both actively and through passive exposure. Participants indicated looking to social media influencers for health and lifestyle inspiration and judged the credibility of sources by appearance and instinct. Health experts should try to use the channels in the way that young adults already use them; use relatable role models on Instagram and YouTube, eye-catching headlines and support groups on Facebook, and easy to follow instruction videos via YouTube. International Registered Report Identifier (IRRID) RR2-10.1111/1747-0080.12448

Obesity, sedentary behaviour, and poor dietary habits amongst young adults are growing concerns, with this age group being in a worse state of health and nutrition than adolescents and adults. This paper presents the procedures for establishing a new instrument for defining behaviours in relation to healthy lifestyle and food choices amongst young adults (Living and Eating for Health Segments: LEHS). The aim of this paper is to outline the instrument design protocol for external validation and to permit replication in other studies. The instrument design process used a multi-step social marketing instrument design method. This approach has previously been used in designing valid and reliable measures in marketing and consumer research, including social marketing. The protocol established six psycho-behavioural LEHS profiles for young adults. These profiles are: Lifestyle Mavens (15.4%), Aspirational Healthy Eaters (27.5%), Balanced-all Rounders (21.4%), Health Conscious (21.1%), Contemplating Another Day (11.2%), and Blissfully Unconcerned (3.4%). Each of these profiles provided insights into psycho-behavioural characteristics that can be used in designing apposite social media social marketing campaigns.

Young adults (YA) are in a critical stage of life for the encouragement of healthy behaviours such as healthy eating and exercising. This research explored Australian YA values and perceptions related to health, healthy behaviours and health promotion efforts. This qualitative analysis involved n = 166, Australian 18–24 year-olds recruited through a market research field house. Participants (63% currently studying at tertiary level) engaged in a facilitated in-depth online conversation around health and healthy eating over four weeks. LeximancerTM and manual inductive thematic coding were utilised for analysis via the lens of emerging adulthood and health communication theories. Health was seen as multi-faceted, with particular importance placed on mental health and exercise. Some participants focussed on physical appearance, often fuelled by comparison to others. Many believed that at their age and health status, adopting health-enhancing behaviours without short-term tangible benefits was not a priority. Participants did not prioritise health-enhancing behaviours due to barriers such as a perceived lack of money, knowledge and time often due to studying or working and perceived effort. Strategies they proposed to encourage healthy eating included: incentivising healthy food; quick and affordable healthy recipes; and communicating the short-term tangible benefits of healthy behaviours. There is a need for focussed health messaging that address the needs and desires of YA and directly address the barriers they face.

Indigenous health outcomes are sought after by governments and communities as a priority. 1,2 In Australia, existing evidence suggests strategies to improve the health of Aboriginal and Torres Strait Islander (hereafter referred to as Indigenous) people must address underlying determinants of health. 3 This includes conceptualising health as biopsychosocial, spiritual and cultural wellbeing, being culturally safe 4 and being led by -or in partnership with and providing back to -the community. 4,5 Yet, a gap remains in the evidence of effective strategies for Indigenous communities.Young Indigenous people, aged 17-24 are an important subgroup of the Indigenous community. Early adulthood has been described as a critical period of development where lifelong habitual behaviours are solidified and opportunities for engagement in society are optimal 6 yet the evidence base for what is effective for health behaviour change for young Indigenous Australians,particularly involving social media sites like Facebook, -is limited. 7 With the increasing use of Web 2.0 (websites that facilitate a more

Background: Poor dietary choices are a risk factor for non-communicable diseases. Young adults have low levels of engagement towards their health and may not see the importance in the adoption of healthy eating behaviours at this stage in their lives. Here we utilise social marketing principles, digital ethnography and online conversations to gain insights into young adults' attitudes and sentiments towards healthy eating. Methods: Young Australian adults who use social media at least twice a day were recruited by a commercial field house. Using a mixture of methods, combining online polls, forums and conversations, participants (n = 195, 18-24 years old) engaged in facilitated discussions over an extended 4 week period about health and eating-related topics. Data were analysed using thematic analysis constant comparison approach. A post-hoc conceptual framework related to religion was theorised and used as a metaphor to describe the results. Results: Findings demonstrate that different segments of young adults with varying attitudes and interest towards healthy eating exist. We developed a conceptual framework based on consumer segmentation which adopted religious metaphors as a typology of 'consumers'. Some young adults practice and believe in the message of healthy eating (saints), whilst some oppose these messages and are not motivated to make any change (sinners), another segment are both aware of and interested in the issues but do not put healthy eating behaviours as a current priority (person in the pew). Conclusions: Consumer segmentation and social marketing techniques assist health professionals to understand their target audience and tailor specific messages to different segments. Segmentation provides insights on which groups may be most easily influenced to adopt the desired behaviours. The typology presented may be a useful tool for health professionals and social marketers to design strategies to engage young adults in healthy eating, particularly those in the pew who are contemplating a change but lacking the motivation. The utilisation of marketing segmentation in health promotion has the potential to enhance health messaging by tailoring messages to specific segments based on their needs, beliefs and intentions and therefore drive the efficient use of resources towards those most likely to change.

Young adults are constantly exposed to energy-dense, nutrient-poor food and beverages, particularly through advertising. Exposure can influence poor food choices and negatively impact health. This study aimed to understand young adults’ attitudes and experiences associated with food-related advertisements, particularly on social media. This qualitative analysis involved n = 166 Australian 18 to 24-year-olds who were involved in a four-week online conversation on different areas relating to health, social media, and eating. Inductive thematic analysis was utilised on two forums on the recall and perceptions of food-related advertisements. Young adults commonly mentioned aspects of the marketing mix (promotion, product, price, and place) in food advertisements. Participants were more readily able to recall energy-dense, nutrient-poor food advertisements compared to healthy food-related advertisements. Digital advertisements were often discussed alongside the use of ad-blockers and algorithms which tailored their social media viewing to what they like. Participants felt constant exposure to unhealthy food advertisements hindered their ability to realise healthy eating behaviours and created feelings of guilt. This current analysis highlights the need to provide an advertising environment that appropriately motivates healthy eating and a food environment that allows healthy food to be the affordable and convenient option.