Social sustainable diets: Supporting the transition to plant-based foods through close relationships

Global meat production has a significant negative impact on the environment. Livestock agriculture is responsible for 12 - 18% of total global greenhouse gas emissions (IPCC, 2019) and contributes significantly to biodiversity loss, deforestation and antibiotic resistance (Godfray et al., 2018). Switching to plant-based diets is a high-impact behaviour that can help reduce greenhouse gas emissions and other environmental impacts by 29-56% (Springmann et al., 2018).

Despite this, many consumers are reluctant to reduce their meat consumption (Bryant, 2019). During my PhD, I found that meat foods were presented to others in more favourable ways than plant-based foods, even by vegans. In addition, there were indicators of dietary polarisation, where plant-based foods triggered strong socio-political and identity-focused reactions.

During an era of increasing social divide, how can societal resistance towards plant-based foods be reduced? The main aim of this Fellowship is to prepare a grant proposal that focuses on whether close social relationships can make the switch to sustainable diets easier for consumers. To support this, I will first conduct a final experiment related to my PhD findings (Project 4), examining whether omnivores and vegans describe plant-based foods in more rewarding ways when they imagine communicating to a close partner, compared to a stranger.

Does focusing on a close partner emphasise the potential reward experience of eating a plant-based food, and thus make it more appealing? I will also measure whether this changes dependent on the dietary preferences of the stranger or close other. This pilot data will be essential for my grant applications to understand the role of close relationships in altering how people think and communicate about sustainable foods.

Then, I will develop a 5-year plan for an effective complex behaviour change intervention (Skivington et al., 2021) that promotes immediate and long-term sustainable food choices through trusted social relationships. Previous work has shown that focusing on relationships can boost health behaviour change (Umberson et al., 2010; Latkin & Knowlton, 2015), and the same may be true for sustainable behaviours.

I will design several mixed-methods studies that investigate whether adopting a plant-based diet is easier with a close friend, romantic partner or family member. This could be for practical reasons (e.g. cooking, shopping), social reasons (e.g. shared focus on rewarding eating experiences), or identity reasons (e.g. forming a new dietary identity together).

I will first conduct a qualitative study, interviewing individuals who live with someone taking part in Veganuary, to establish how exposure to plant-based consumption practices may bridge the vegan-omnivore divide. Another study will examine whether giving a plant-based meal subscription (e.g. allplants) to a couple versus an individual can lead to long-term reductions in meat consumption.

A further longitudinal study will measure the processes involved in dyadic relationships and behaviour change are the same for romantic partners as for close friends, flatmates or family members. Additional studies will take a social-network approach to measure the scope of influence from a couple's sustainable dietary choices, and will measure how couples communicate about food during their dietary transition.

The final set of studies will form a complex intervention measure to motivate plant-based consumption via encouragement from a close partner.

This grant proposal will incorporate interdisciplinary methodologies to directly assess the climate impact of the intervention. For example, I will work with a modeler to estimate the carbon emissions saved by a consumer adopting a plant-based diet with the support of a close partner. This proposed research will tackle resistance to plant-based diets by treating couples as a whole social entity, doubling the reduction in carbon emissions if successful.