Social networks’ role in vegetarian diet adoption and 1 maintenance: 2 A prospective study from the northern Netherlands

Wider adoption and maintenance of vegetarian diets would be mutually benefi- 11
cial for human and environmental health. Social networks have been identified as a 12
factor that would support this transition. While social networks’ role in vegetarian 13
diet adoption has been studied, their role in vegetarian diet maintenance over time 14
has received much less attention. To address this gap, we investigated the extent 15
to which having a vegetarian close tie (family member or partner) was related to 16
a participants’ likelihood of eating vegetarian. Data were derived from Lifelines, a 17
large cohort study from the northern Netherlands (n = 60,639). Two assessments 18
an average of 3.9 years apart were used. We studied the interaction of close ties’ 19
diet trajectories (either vegetarian or omnivore) at baseline and follow-up, and their 20
relationship to participants’ own diet trajectories at baseline and follow-up. Mixed 21
multinomial logistic regression was used to account for clustering among families. 22
Participants closely mirrored their close ties’ diet trajectories. Having close ties who 23
were vegetarians at baseline and follow-up was associated with the highest prob- 24
ability of the participants themselves also being vegetarians at both assessments 25
(Pr=0.08, 95% CI: 0.07 - 0.08). In contrast, participants with no vegetarian close 26
ties at baseline and follow-up were the least likely to be vegetarians themselves at 27
both assessments (Pr=0.02, 95% CI: 0.02 - 0.02). Partners particularly had a strong 28
influence on participants’ diet trajectory compared to other family members. It 29
appears that the closer the tie is, the stronger the influence onparticipants’ diet 30
trajectory. Leveraging social networks could be effective in encouraging more wide- 31
spread adoption and maintenance of vegetarian diets.