Ultra-processed foods consumption and diet quality during shift work among healthcare workers: a within-subject design
摘要
While ultra-processed foods (UPF) consumption is a key determinant of metabolic health, within-subject evidence evaluating shifts in UPF intake is limited. This study compared UPF consumption and dietary quality between shift and non-shift days among healthcare workers.
MethodsThis within-subject observational study included 60 healthcare workers with rotating shift schedules. Four 24-hour dietary recalls (two shift days and two non-shift days) were obtained by a trained dietitian. Foods were classified by the NOVA system, and the UPF energy contribution percentage (UPFECP) was calculated. Diet quality was assessed using the Diet Quality Index (DQI). Nutrient intakes and meal patterns on shift and non-shift days were compared using paired statistical analyses. Additionally, hierarchical linear regression models were used to examine the association between condition-specific UPFECP and DQI total scores after adjustment for age, sex, body mass index, and prior nutrition education.
ResultsCompared with non-shift days, shift days showed lower daily energy intake (2624.8 ± 816.5 vs. 2826.6 ± 857.8 kcal, p = 0.025). On shift days, the energy contribution of unprocessed/minimally processed foods decreased (from 48.5% to 42.4%, p < 0.001), whereas UPF increased (from 8.6% to 11.8%, p = 0.002). While the overall frequency of meal skipping did not differ significantly between conditions (p = 0.261), the specific meals skipped showed a distinct shift (p < 0.001). Higher UPF consumption during the shift was associated with lower DQI total and DQI adequacy scores (p = 0.003 and p < 0.001, respectively). In adjusted hierarchical regression analyses, UPFECP was independently and inversely associated with DQI total score on shift days (B= -0.411, 95% CI: -0.660 to -0.161, p = 0.002), whereas no significant association was observed on non-shift days.
ConclusionShift work was associated with increased UPF consumption and poorer diet quality despite lower total daily energy intake. These findings suggest that shift-related working conditions may promote unfavorable dietary patterns characterized by a greater reliance on UPF. Improving access to unprocessed/minimally processed food options during night shifts may represent a practical strategy to support the nutritional health of healthcare workers.