Abstract

Background
Living on a low income is associated with multiple interacting factors and mechanisms that contribute to less healthy diets. Yet research has rarely examined these systemic drivers in depth among people on low incomes, including the perspectives of both citizens with experiential knowledge as well as professionals. Therefore, this study aimed to gain insights into the complex system dynamics underlying dietary behaviour of people on a low income, from the perspective of both citizens with experiential knowledge and professionals.

Methods
This study applied a participatory, system-based approach. Three group model building sessions were conducted in a Dutch municipality (November 2024); one with citizens with experiential knowledge (n = 15); one with professionals with expertise in the field of food, nutrition, health, social support (e.g., financial, family), involved in policies or working directly with people living on a low income and/or those facing diet/health-related issues (n = 13), and one combined session with both groups. During the first two sessions, citizens and professionals created separate Causal Loop Diagrams (CLDs) including factors and mechanisms influencing dietary behaviour. During the third session, citizens and professionals identified leverage points for change and corresponding actions to facilitate healthier dietary behaviour for people on a low income. The research team merged the separate CLDs and actions proposed into one integrated CLD and action list, after the sessions.

Results
The perspectives of citizens with experiential knowledge and professionals overlapped and complemented each other well, leading to an integrated CLD with 62 factors. Seven subthemes were identified: (1) Government and policy, (2) Food industry, (3) Social and societal factors, (4) Food environment, (5) Resources and daily living conditions, (6) Mental and physical wellbeing, and (7) Individual behaviour and characteristics. The CLD revealed three core dynamics underlying dietary behaviour of people on a low income: scarcity and reduced wellbeing, the unhealthy food environment, and social and societal barriers. Citizens and professionals proposed 30 actions addressing these dynamics for systemic change.

Conclusions
This study yielded insights into the complex system that complicates healthy eating for people on a low income, based on the perspectives of citizens and professionals. Actions at different system levels are needed to facilitate healthy dietary behaviour among people on a low income. In this, it is essential to involve professionals as well as citizens with experiential knowledge in the development of policy and support services.