Exploring Perceived Barriers and Facilitators to Healthier and More Sustainable Dietary Behavior in 27 European Countries: Protocol for a Cross-Sectional Survey.

Background: Food systems strongly affect human and environmental health. Across Europe, they often generate negative public health and environmental outcomes and contribute to inequalities in access to healthy, sustainable food. Addressing these challenges requires understanding the complex dynamics of the interaction of individual behavior within food systems, which involves a combination of internal mechanisms and external influences. Objective: This study, part of the FEAST project (Food Systems That Support Transitions to Healthy and Sustainable Diets), aims to increase understanding of how micro-, meso-, and macro-level factors shape Europeans' food preferences, purchasing, and consumption behaviors. It also explores differences across European regions and population subgroups. Methods: A cross-sectional survey was conducted among 27,000 adults in 27 European countries across the 5 FEAST food regions (Anglo-Saxon, Central European, Scandinavian, Southern European, and Eastern European). In addition to the vulnerable groups (older adults; low-income or low-education people and those with health or disability conditions; families with minors, women, gender-diverse people, etc) that could be captured in the main survey, an additional sample of 400 vulnerable individuals from the Down syndrome (DS) community (including carers of people with DS) was expected to be involved in 5 European countries (Ireland, Italy, Portugal, Romania, and Scotland). To achieve the target of 1000 participants per country, the general population was recruited through a market-insights platform with extensive European coverage. Individuals with DS and their caregivers were recruited through national DS associations. Data were collected using an 88-item questionnaire covering dietary patterns, food-purchasing behavior, drivers and barriers to healthy and sustainable eating, perceived dietary sustainability, opinions on food policy options, and sociodemographic characteristics. The same questionnaire was administered to caregivers, whereas individuals with DS completed an adapted version addressing eating habits, food appearance, and food neophobia in an accessible format. Statistical analyses are being conducted to identify determinants of healthy and sustainable diets. Results: A total of 27,417 questionnaires were collected from the general population across 27 countries, together with 82 questionnaires from people with DS and 242 from caregivers. Expected findings will describe Europeans' food consumption habits, preferences, and purchasing behaviors, including those of vulnerable groups, and assess their alignment with planetary health diet principles. The study will also identify key barriers and facilitators to adopting healthier and more sustainable diets, as well as sources of nutritional information and attitudes toward food-related policies. Conclusions: The findings will support our understanding of individual dietary habits and the development of multilevel strategies to promote healthier and more sustainable diets in these population subgroups across Europe. They will also provide insights into interactions between consumers and the food system, highlighting barriers and facilitators that influence dietary choices.