Association between sustainable dietary patterns and body weight, overweight, and obesity risk in the NutriNet-Santé prospective cohort.

BACKGROUND: Improving the sustainability of current food systems may prevent future public health, environmental, and social concerns.

OBJECTIVE: Our objective was to investigate the associations between sustainable dietary patterns, assessed using the Sustainable Diet Index (SDI), and the risk of obesity, overweight, and weight gain in French adults, with a prospective design.

METHODS: In 2014, the SDI was computed among 15,626 participants of the NutriNet-Santé study (of whom 76% were women) using data collected within the BioNutriNet project. The SDI ranges from 4 (lowest sustainability) to 20 points and includes 4 subindexes representing the 4 pillars of a sustainable diet. Longitudinal data of weight and height were collected yearly from 2014 to 2018. We used mixed models to estimate the associations between sex-specific quintiles (Qs) of the SDI and weight change and Cox proportional hazard models with different levels of adjustments to assess the association between sex-specific Qs of the SDI and risk of obesity and overweight (mean follow-up time: 2.8 y).

RESULTS: At baseline, a higher percentage of participants with overweight was observed in the first SDI Q, reflecting the lowest sustainable dietary patterns (Q1), than in Q5 (29.83% compared with 12.71%). Compared with Q5, a slight increase (at the population level) of almost 160 g/y was observed in Q1, whereas weight remained relatively stable among participants in other Qs. In total, 281 incident cases of obesity and 777 cases of overweight were identified during the follow-up. Participants in Q1 had a higher risk of obesity and overweight than participants in Q5 (HR comparing Q1 with Q5: 4.03; 95% CI: 2.42, 6.10; P-trend < 0.001; and HR comparing Q1 with Q5: 1.49; 95% CI: 1.13, 1.95; P-trend < 0.001, respectively).

CONCLUSIONS: The findings support a potential protective role for more sustainable diets to prevent the risk of weight gain, overweight, and obesity.This trial was registered at clinicaltrials.gov as NCT03335644.