Towards Healthy and Sustainable Living: Theories and Interventions for Behaviour Change

Climate change and non-communicable diseases (NCDs) represent two of the greatest threats to human well-being in the 21st century. Both are strongly influenced by human behaviour, making behavioural change a critical pathway for mitigating climate and health risks. This chapter explores how selected theories and models from health and environmental psychology can inform the development and implementation of interventions that promote both healthy and sustainable behaviours. It then presents effective interventions targeting psychological factors as well as more structural aspects (e.g., infrastructure and policy) in high-impact behavioural domains such as mobility (reducing car use and promoting active transport) and diet (reducing meat consumption and increasing the intake of healthy plant-based foods). Finally, the chapter discusses the limitations and future directions of current behaviour change approaches, calling for greater representation of diverse populations, more long-term evaluations, consistency in measured outcomes, and greater attention to the broader context in which behaviours occur. Overall, this chapter advocates for multidisciplinary and multilevel interventions that address both individual and contextual determinants of behaviour. It aims to inspire researchers, practitioners, and policymakers to strengthen the scientific and societal relevance of behavioural strategies in the transition toward healthier and more sustainable lifestyles.