The few available studies in the Caribbean, including the French West Indies, highlight urgent public health issues: a shift in the dietary structure and increasing rates of obesity and chronic diseases have been observed over recent decades, revealing an advanced phase of the nutrition transition, which may affect nutrition security. Among the striking characteristics of nutrition transition are changes in food supply and population diet over short periods related to international trade and increased dependence on foods’ importation. An in-depth knowledge of individual and environmental determinants of dietary behaviours in French West Indies is urgently needed to better understand how they impact population health and to guide public health measures. Our multidisciplinary project, involving nutritionists, epidemiologists, economists, sociologists, sensory scientists, a food technical institute, food industries and the French Ministry of Agriculture, aims to elucidate the relationships between characteristics of local food supply and dietary behaviours of populations and to propose strategies to improve nutrition security in the French West Indies. Specifically, our project aims at: -characterizing individual food and nutrient intakes, nutritional status and household food supply practices (WP1). Based on epidemiological representative studies conducted in 2004 among 1113 Martinican adults and in 2014 among 1273 Martinican and Guadeloupean adults and 153 children, we will characterize dietary patterns, in relation with the prevalence of obesity, folate and iron deficiencies as well as their social determinants and their evolution over 11 years. -understanding determinants of consumers’ food choices (WP2). We will assess sensory preferences for sweet, fat and salt in Martinican adults, by developing sensory tests and preference questionnaire adapted to the population. We will study their relationships with dietary intake, through 24h dietary records. We will also evaluate how consumers balance different motives (price, sensory preference, product characteristics, local production) using experimental economics. Then, we will qualitatively explore how food environment influence consumers’ food practices. -characterizing the evolution of food supply and the rooms for manoeuvre for local firms to improve the nutritional quality of foods (WP3). Using interviews, we will characterize supply chain and strategies of different stakeholders in the French West Indies. We will study dynamics of food products’ importations and local production in terms of price, amounts, nutritional quality and types of foods, over two decades in Martinique and Guadeloupe, using existing data from custom duties and local production. Rooms for manoeuvre for local firms, in terms of nutritional improvement of foods (reformulation, redeployment and innovation) will be estimated. -exploring strategies, at consumer and food supply levels, able to improve nutrition security. Based on findings on firms’ rooms of manœuvre, we will simulate the impact of reformulations on the nutritional quality of individual observed diets, i.e. when no changes occur at consumer level. Based on findings on consumers’ behaviours, and when no changes occur at food supply level, we will model the dietary changes allowing meeting nutritional recommendations with lowest departure from observed food patterns and at no additional cost. Then, the potential impact on nutrition security of combining improvements of food supply and food choices will be explored through quantitative and qualitative approaches, in order to suggest guidelines for public and private decision makers. By proposing ways to improve nutrition security through more favorable dietary behaviors and local food supply accessible and conducive to well-being and health, our project will contribute to identify and to promote strategies to meet the nutritional and hedonic needs of consumers under their budget constraints.