LAUSR

Purpose Circadian misalignment has been associated with an increased risk of overweight and obesity, as well as changes in metabolic parameters. This study evaluated the association between social jet lag (SJL), a measure of circadian misalignment, and anthropometric, metabolic and food intake outcomes 6 months after bariatric surgery. Materials and Methods A total of 122 bariatric patients were included (77% female, aged 33 years (range 28–41); 79.5% underwent Roux-en-Y gastric bypass). Anthropometric, food consumption and SJL were evaluated in the preoperative evaluation and in the third and sixth months after surgery. SJL was calculated based on the absolute difference between the mid-sleep time on weekends and weekdays. Generalised estimating equations and linear regression were performed to evaluate the associations between mean SJL exposure and the outcomes. Results The interaction between SJL and follow-up time negatively influenced the evolution of weight ( p  = 0.01), BMI ( p  = 0.04) and insulin levels ( p  = 0.01). SJL had an effect on intake of calories ( p  = 0.001), carbohydrate ( p  = 0.005) and total ( p  = 0.007), monounsaturated ( p  = 0.03) and polyunsaturated fat ( p  < 0.001). Linear regression showed a negative association between mean SJL exposure over the 6 months and the percentage of weight loss (coefficient = − 0.30, p  = 0.006), body weight loss (kg) (coefficient = − 0.17, p  = 0.03) and the reduction of BMI (coefficient = − 0.24, p  = 0.007). Conclusions SJL was negatively associated with anthropometric, metabolic and food consumption outcomes 6 months after bariatric surgery. Future studies with longer follow-up are needed to confirm these findings. Trial Registration Clinical Trials.gov : NCT03485352