Background: Rising rates of chronic disease, combined with the threat of climate change, have increased the need to promote healthy, low-carbon (HLC) lifestyles globally. Nevertheless, most research in this area has focused on single behaviours in isolation, at the expense of understanding these lifestyles more broadly. This thesis aims to advance current knowledge of the patterning, prevalence, and predictors of health- and climate-relevant lifestyles in the UK, based on combinations of travel and dietary behaviour. Methods: Two datasets, the National Diet and Nutrition Survey and UK Biobank, were used to explore this aim. Walking, cycling and public transport use were considered forms of HLC travel; lower consumption of red and processed meat (RPM), combined with higher consumption of fruit and vegetables (FV) were considered markers of a HLC diet. Study 1 examined associations between travel modes and dietary consumption. Study 2 estimated the prevalence of different health- and climate-relevant lifestyles using latent class models to identify unique patterns of travel and dietary behaviour. Study 3 explored which socio-demographic factors and types of influences were associated with each lifestyle pattern. Analyses were stratified by gender and findings were compared across both datasets. Results: HLC travel, particularly cycling, was associated with consumption of higher FV and lower RPM. More car travel tended to cluster with higher RPM consumption, and much of the samples (47-80%) had multiple unhealthy, high-carbon (UHC) behaviours. Entirely HLC lifestyles were rare (2-5%) but a sizable minority had lifestyles that were predominantly or partially HLC. UHC lifestyles were socio-demographically diverse, but HLC lifestyles were consistently associated with higher qualifications, reduced car access, and living in urban settlements, more deprived areas, and in London. Conclusions: HLC and UHC behaviours both cluster to some degree, which suggests that each lifestyle pattern may be driven by common influences. Socio-economic and environmental factors were the most important predictors of HLC lifestyles. These findings provide a more comprehensive understanding of health- and climate-relevant behaviours in the UK and give greater insights into the full impacts of people’s lifestyles.
