Social norms and young adults' self-reported meat and plant-based meal intake: Findings from two online cross-sectional studies.

Plant-based eating is beneficial for human and planetary health. It is important to identify factors which may encourage people to reduce meat, and increase plant-based meal intake. Perceived social norms are associated with meat and plant-based meal intake in adults, however, less is known about the relationship between perceived social norms and young adults' own self-reported meat and plant-based eating in general, and in different social contexts. Across two online studies we examined this. In Study 1 (n = 217 young adults, aged 18-25 years, mean age = 19.50 years, SD = 1.37 years, mean BMI = 24.21, SD = 5.45, 91% cisfemale, 92.0% omnivores), perceived descriptive (the perceived behaviour of others) and injunctive (the perceived approval of others) norms were measured in general. In study 2 (n = 151 young adults aged 18-25 years, mean age = 19.62 years, SD = 1.50 years, mean BMI = 24.32, SD = 4.99, 88.8% cisfemale, 71.1% omnivore), perceived descriptive and injunctive norms were examined in a variety of social contexts. In Study 1, perceived descriptive norms about friends were associated with self-reported meat, and descriptive norms about peers and friends, and injunctive norms about friends were positively associated with self-reported plant-based meal intake. In Study 2, descriptive norms about friends were associated with self-reported meat intake in fast-food restaurants and at friends' houses, and injunctive norms about friends were associated with meat intake in restaurants. There were no other significant associations between either type of social norm and meat or plant-based meal intake. We provide the first evidence that peers and friends may be relevant for plant-based meal intake, and only friends may be relevant for meat intake. Further research is needed to examine people's actual food intake, and in longitudinal studies to rule out reverse causality.

The influence of experimental confederate peers on children's food intake: A systematic review and meta-analysis.

Confederates influence eating behaviour. Systematic reviews and meta-analyses have been conducted on this topic, however, the majority have examined adults, or a combination of adults and children, therefore, an up-to-date meta-analysis is needed to examine the impact of confederate peers on children's food intake. We systematically reviewed and meta-analysed the influence of confederate peers on children's food intake in research using present and remote-confederates. Six publications summarising findings from seven studies were included in this review. One publication was excluded from the meta-analysis because it was not possible to extract the required data. The meta-analysis showed that children were influenced by confederate peers; eating more when exposed to a high-intake compared to a no or low-intake confederate. Larger effects were observed when children were exposed to a remote-than a present-confederate, and for studies using healthy snacks compared to high fat high sugar (HFHS) snacks. No difference in effect size was observed when children were exposed to a high-vs. low-intake confederate compared to a high-vs. no-intake confederate. In the narrative synthesis, confederate intake influenced children's eating behaviour 24-h later, and possible moderators and a potential mechanism underlying the influence of confederates were identified. Caution is needed when interpreting the results, as the sub-groups were not compared statistically due to high heterogeneity, and a small number of studies were included in this review. Furthermore, all studies using the present-confederate design examined HFHS snack intake, therefore, it is unclear whether observed differences in effect sizes between present- and remote-confederates may be due to confederate or food type. Research is needed to further examine the influence of confederate peers on children's food intake and to examine mechanisms and moderators.

The role of perceived descriptive and injunctive norms on the self-reported frequency of meat and plant-based meal intake in UK-based adults.

Perceived social norms refer to beliefs that people hold about what other people do (descriptive norms) and approve of (injunctive norms), and are associated with food intake. However, less is known about whether perceived social norms are associated with meat and plant-based meal intake. Using a cross-sectional survey design 136 participants (aged 19-66 years, mean age = 39.63, SD = 12.85 years, mean BMI = 25.77, SD = 5.30, 80.9 % female, 77.9 % omnivores, 22.1 % flexitarians) answered questions about how frequently they consumed meat and plant-based meals, and how frequently they perceived people in their social environment to consume (perceived descriptive norms), and approve of consuming (perceived injunctive norms) meat and plant-based meals. Perceived descriptive and injunctive norms were positively associated with participants' frequency of meat intake: participants ate meat more frequently when they perceived their significant other to frequently eat meat (descriptive norm), and when they perceived their significant other and friends to approve of (injunctive norm) frequently eating meat. Perceived descriptive norms were positively associated, but injunctive norms were negatively associated with participants' frequency of plant-based meal intake: participants ate plant-based meals more frequently when they perceived their extended family, friends, and significant other to frequently eat plant-based meals. However, participants ate plant-based meals more frequently when they perceived their extended family to approve of less frequent plant-based meal intake. These results suggest that different social groups may be important for meat and plant-based meal intake, with significant others and friends appearing to be important reference points for both food types. Further research examining the contexts in which the different social groups influence eating behaviour would be of value.