Seconda L, Egnell M, Julia C, et al. - Researchers here examined how sustainable dietary patterns, assessed using the Sustainable Diet Index (SDI), are associated with the risk of obesity, overweight, and weight gain in French adults, with a prospective design. Using data collected within the BioNutriNet project, the SDI was determined among 15,626 participants of the NutriNet-Santé study (of whom 76% were women) in 2014. The first SDI quintile (Q) had a higher percentage of participants with overweight at baseline, indicating the lowest sustainable dietary patterns (Q1), than in Q5 (29.83% compared with 12.71%). Relative to Q5, those with Q1 had a slight increase (at the population level) of almost 160 g/y, whereas participants in other Qs had relatively stable weight. Findings indicate that more sustainable diets have a potential protective role in preventing the risk of weight gain, overweight, and obesity.