Differences in food intake and subjective perceptions of food between day and night shift workers over 24 hours

Introduction: Shift work is a common scheduling practice in contemporary society due to the ongoing demand for specific products and services throughout the 24-hour day. Research has established associations between shift work and the developing obesity and metabolic disorders, and the dietary intake during nighttime seems to increase the risk of these conditions. Nevertheless, it remains unclear if hunger, food preferences, and satiety differ between night workers and day workers. This study aimed to compare the daily patterns of dietary intake and subjective dietary perceptions among day and night workers. Our hypothesis suggests that night workers are more likely to concentrate their meals during the nighttime hours. Furthermore, it is expected that night workers would have a greater appetite for indulgent foods, which are typically high in fat, sugar, and sodium, compared to day workers.

Methods: A cross-sectional study was conducted with sixty workers (30-day workers and 30-night workers) employed in the healthcare sector at the Public Hospital in Uberlândia city, Minas Gerais State, Brazil. Dietary intake was assessed using a daily food record for an entire workday, accompanied by a Numerical Rating Scale used to measure subjective feelings of food satisfaction after each meal. To examine dietary intake throughout the day, the day was divided into four periods: P1 (6am - 10:59am), P2 (11am - 3:59pm), P3 (4pm - 8:59pm), and P4 (9pm - 5:59am). Generalized Estimated Equations (GEE) were employed to compare meal distribution throughout the day and subjective food perception for each meal among day and night shift workers.

Results: Night workers had higher energy intake (p = 0.046) during P4, along with an increase in calories derived from protein (p = 0.035), the corresponding percentage (p < 0.001), and calories derived from lipids (p = 0.03) compared to day workers. Furthermore, night workers showed a stronger preference for vegetables during the evening snack (p < 0.001) and a greater appetite for meat, eggs, and savory foods during the morning snack (p < 0.001 and p = 0.007, respectively) compared to day workers.

Conclusion: Night workers demonstrated higher night food consumption compared to day workers. Additionally, the subjective food perceptions of night workers exhibited minor variations from those of day workers. Further research is needed to gain a more comprehensive understanding of the long-term meal distribution patterns and appetite for various food groups throughout the day. Support: CNPq.

Publication History

Article published online:
08 October 2025