Aurélie Cotillard1,2*, Sean P. Kennedy3*, Ling Chun Kong1,2,4*, Edi Prifti1,2,3*, Nicolas Pons3*, Emmanuelle Le Chatelier3, Mathieu Almeida3, Benoit Quinquis3, Florence Levenez3, Nathalie Galleron3, Sophie Gougis4, Salwa Rizkalla1,2,4, Jean-Michel Batto3, Pierre Renault3, ANR MicroObes Consortium‡ Joel Doré3, Jean-Daniel Zucker1,2,5, Karine Clément1,2,4†, Stanislav Dusko Ehrlich3†

[Abstract]:  Complex gene-environment interactions are considered important in the development of obesity1. The composition of gut microbiota can determine the efficacy of energy harvest from food2,3,4 and changes in dietary composition have been associated with changes in the composition of gut microbial populations5,6. The capacity to explore microbiota composition was dramatically improved due to the development of metagenomic approaches7,8, which have already allowed establishing the first human gut microbial gene catalogue9 and stratifying individuals by their gut genomic profile into different enterotypes10, but the analyses were carried out mainly in non-intervention settings. To investigate the temporal relationships between food intake, gut microbiota and metabolic and inflammatory phenotypes, we conducted diet-induced weight loss and weight stabilization interventions in a study sample of 38 obese and 11 overweight individuals. Here we report that individuals with reduced microbial gene richness（40%）present more pronounced dys-metabolism and low-grade inflammation, as observed concomitantly in the accompanying paper11. Dietary intervention improves low gene richness and clinical phenotypes, but appears to be less efficient for inflammation variables in individuals with lower gene richness, which thus may have predictive potential for the efficacy of intervention.