Dietary pattern trajectories in French adults of the NutriNet-Santé cohort over time (2014-2022): role of socio-economic factors.

Despite the urgent need for plant-based dietary shifts, few studies have examined current diet trajectories using longitudinal data. This study analyzed dietary transitions of French adults over 8 years (2014-2022), assessing diet quality and the role of various socio-economic factors. Consumption data from 17 187 NutriNet-Santé cohort participants, weighted for the French Census, were collected via FFQ in 2014, 2018 and 2022. Adopting a gender-specific approach, consumption changes in twenty-three food groups were assessed over time. Diet quality was evaluated using the Comprehensive Diet Quality Index score, categorising foods into 'healthy' and 'unhealthy'. Socio-economic analysis targeted four food groups (red meat (including fresh beef, pork, offal and lamb), processed meat (e.g. sausages, ham and bacon), legumes and whole-grain products), strongly linked to mortality risk and recognised as significant markers of the sustainable diet transition. All analyses were conducted using multi-adjusted mixed-effects models. Consumption of some healthy plant-based foods (nuts +59 %, legumes +22 %, whole-grain products +7 %) significantly increased over time, while consumption of some unhealthy foods (red meat -19 %, refined cereals -18 %, sweetened drinks -15 %) decreased. Conversely, consumption of prepared and mixed dishes (+16 %) and processed meat (+35 %) increased. These changes differed in magnitude between genders and translated into an improved diet quality score (Comprehensive Diet Quality Index). Occupational status was linked to longitudinal changes in food consumption, showing increased consumption of plant-based foods among students and higher socio-professional categories. Our findings provide accurate data on trends and factors for targeted initiatives, guiding strategic interventions for a sustainable dietary transition.