Eating by the Norm: The Influence of Social Norms on Young People's Eating Behavior

Research output: ThesisDoctoral thesis 1 (Research UU / Graduation UU)


Humans are social beings. Our identities are, for an important part, shaped by the different groups we belong to. Each social group has its own standards or norms for behavior, based upon what is considered good or correct behavior within that social group. Such socially shared norms are usually not made explicit, but become apparent through observing the behavior of group members and through understanding the expectations they have for how others in their social group should behave. The influence that social norms exert over an individual may be most pronounced in young people, who are still looking to establish their social identity and are especially sensitive to group influences. In the current dissertation, we examined how social norms influence the behavior of young people in the context of eating behavior. More specifically, the focus of this dissertation was to investigate if social norms can be effectively used to promote healthy eating behavior among young people. In five empirical chapters, we reported the findings of a systematic literature review, a large-scale cross-sectional survey, and various experimental studies conducted both in the laboratory and in the field. Results indicated that social norms are associated with young people’s eating behavior, and that intervening in the peer group norms governing eating behavior can affect young people’s food consumption. Several important moderators and boundary conditions were identified. Peer social norms that encourage healthy eating seem to be more effective in promoting healthy eating behavior than peer norms that discourage unhealthy eating were only (inversely) related to healthy eating intentions, but not to actual intake of either healthy or unhealthy foods. Moreover, descriptive peer norms (which indicate the actual behavior of other group members) were found to be more effective in promoting healthy eating in young people than injunctive peer norms (which indicate the behavior that other group members would approve of). The extent to which students feel similar to their fellow students may be a crucial moderator of the impact of peer norm manipulations on eating behavior. Finally, we found that young people to whom a healthy peer social norm was communicated reported higher self-identification as a healthy eater, more positive attitudes toward eating healthily and higher self-efficacy for eating healthily. Self-identification, attitude and self-efficacy partially mediated the effect of the majority norm on participants’ intentions to eat healthily in the near future, suggesting that increases in these variables might be part of the mechanism through which descriptive social norm interventions lead to positive effects on eating behavior. Taken together, the studies in this dissertation indicate that social norms play a substantial role in young people’s eating behavior. Moreover, social norms can be used to promote healthier eating behavior among young people, as long as the moderators and limitations described in this dissertation are taken into account. For example, health promoters should carefully determine the type of social norms they wish to influence, as well as the kind of eating behavior they target with their norm intervention. If such boundary conditions are taken into account, interventions aimed to promoting healthier social norms can be an effective part of a process in which changing norms contribute to healthier eating behavior among young people.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Utrecht University
  • de Ridder, Denise, Primary supervisor
  • de Wit, John, Supervisor
  • de Vet, E., Co-supervisor, External person
Award date31 Jan 2014
Print ISBNs978-90-393-6078-1
Publication statusPublished - 31 Jan 2014


  • social norms
  • descriptive norms
  • adolescents
  • eating behavior
  • healthy eating
  • health promotion


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