The nutritional and metabolic impact of night shift work in a real-world setting

Abstract Growing evidence from epidemiological and lab-controlled studies links night shift work to adverse health outcomes, but evidence from real-world occupational environments remains limited. Using multiple wearable devices and mobile health apps, alongside other objective and subjective assessment tools, we assess nutritional intake and cardiometabolic parameters among 72 shift workers recruited from a single-center Swiss hospital (82% female; median age 31 years; body mass index 22.7 kg/m 2 ) during three consecutive night shifts and three consecutive day shifts. While intake of calories, protein, and fat is reduced during night shifts, glycemic variability and postprandial glucose spikes are increased compared to day shifts. After three consecutive night shifts, plasma cortisol is reduced, and the 24-h heart rate and heart rate variability are altered. Exploratory analysis reveals higher protein intake correlates with lower glycemic variability, whereas nighttime eating is associated with increased glycemic variability. Future interventional studies should explore whether adjusting meal composition and timing could improve glycemic variability in night shift workers.