Greater fragmentation of the daily rhythm of energy intake is associated with better insulin sensitivity in rotating shift workers.

Shift workers are essential to sustaining the modern 24 h society. However, they experience a higher risk of developing metabolic syndrome, a vulnerability thought to arise from recurrent misalignment between their sleep-wake and fasting-eating schedules. This study aimed to investigate the association between the daily rhythms of energy and macronutrient intake, motor activity (MA), and wrist temperature (WT) with anthropometric and biochemical parameters in rotating shift workers (RSW). Thirty male RSW participated in this 10 d cross-sectional study. Anthropometric and biochemical measurements were collected, and a 10 d 24 h food recall was used to assess energy and macronutrient intake. From these data, daily rhythms of energy intake were characterized, and actigraphy was used to evaluate daily rhythms of MA and WT. Daily rhythms were analyzed using non-parametric analyses including the intradaily variability (IV) and interdaily stability (IS), and associations with outcome variables were tested using partial correlations. A negative association was observed between the IV of the daily rhythms of energy and carbohydrate intake with insulin levels (p < 0.05), HOMA-IR (p < 0.05), and triglycerides (p < 0.05). In contrast, higher IV in the daily rhythm of WT was associated with higher total cholesterol (p < 0.05) and LDL-cholesterol (p < 0.05). These results suggest that a higher fragmentation (higher IV) of the daily rhythm of energy intake is associated with better glucose tolerance among RSW.