Abstract
: Despite the urgent need for sustainable dietary transitions, few studies have examined current dietary trajectories using longitudinal data. This study aimed to identify dietary consumption trajectory profiles over an 8-year period (2014-2022) while assessing their sustainability in a multicriteria approach. Consumption data from NutriNet-Santé cohort participants were collected using FFQs in 2014, 2018 and 2022. Dietary trajectory profiles were modeled using group-based multi-trajectory based on factors from Principal Component Analysis on energy-adjusted consumption data (n = 17,187). Profiles were analyzed for sustainability (environmental and nutritional dimensions) using multi-adjusted mixed-effects models. Six trajectory profiles (P) were identified. P0 (considered as reference) had average consumption for all food groups, with increased plant-based intake over time. In comparison, P1 had the highest baseline alcohol (+301%) and offal intake, increasing processed meat (+74%) and decreasing offal over time. P2 had higher milk (+187%) and sweet drinks intake, increasing animal substitutes (+1737%) and whole-grain products. P3 had higher nuts (+680%) and legumes intake, increasing egg (+166%) and reducing fruit juice. P4 had high fish (+39%) and fruit intake, increasing butter (+53%) and reducing alcohol. P5 had higher pork (+143%) and red meat intake, increasing fish (+31%) and reducing dairy. Initially, P3 and P4 had the lowest GHG emissions (-18%, -49% vs. P0), best nutritional profiles, and higher organic food consumption. P5 had the greatest environmental impact (+51%) and the lowest nutritional scores. Over time, P0 reduced GHG emissions and improved nutritional scores. P3 and P4 showed minimal changes, while P5 had the greatest GHG emissions decrease (-14%) and nutritional quality improvements. Identifying ongoing dietary transition trajectories, our findings contribute to optimizing targeted actions aimed at promoting sustainable dietary consumption habits. KEY MESSAGES: • Regardless of initial dietary preferences, French adults exhibit an overall trend over time towards increased intake of plant-based foods and decreased intake of red meats, at varying scales. • French adults exhibit varying degrees of transition towards more sustainable diets, with an overall decrease in GHG emissions from food consumption and an improvement in their nutritional profiles.