Meal timing and risk of metabolic syndrome in the prospective French NutriNet-Santé biobank

Abstract Background Circadian rhythm disruption has been associated with higher risks of cardiometabolic diseases and several cancers. Mistimed eating patterns can desynchronize circadian rhythms, and could therefore influence metabolic health. However, long-term associations between meal timing and the metabolic syndrome remain unclear. The aim of this study was to evaluate the prospective associations between meal timing and the risk of developing metabolic syndrome. Methods We used measured biological and clinical data from 16 353 adults (51 years ± 13.72) in the NutriNet-Santé biobank (2011-2014), and examined the associations between meal timing, assessed with repeated 24-hour dietary records during the first two years of follow-up (starting 2009), and the risk of metabolic syndrome, using modified Poisson regression models, adjusted for main confounders. Results At the end of follow-up (mean 2.1 years (SD = 1.2)), a later timing of the first meal of the day was associated with a moderately higher risk of metabolic syndrome (1,788 cases; RR per 1-hour delay = 1.05; 95% CI: 1.00-1.10). However, after adjusting for overall diet quality, this association was attenuated (RR: 1.04; 95% CI: 0.99-1.09). Overall, we found no evidence of an association between the occurrence of metabolic syndrome and the time of the last meal (RR: 0.99; 95% CI: 0.95-1.05), the number of eating occasions (RR: 1.00; 95% CI: 0.98 - 1.03), or night-time fasting duration (RR: 1.03; 95% CI: 0.99 1.07). Conclusions In this large prospective study, timing of the first meal showed modest associations with metabolic syndrome. Further investigations using a longer follow-up are needed to elucidate how meal timing influences metabolic health. Key messages • Beyond the nutritional quality of meals, meal timing, particularly time of first meal, may be an accessible prevention strategy for metabolic health. • More largescale prospective and intervention studies are needed to better understand the links between meal timing and metabolic health.