Effect of consuming a late-night high-protein/moderate-carbohydrate vs. low-protein/high-carbohydrate meal by night workers on their food perceptions later during the day: a randomized crossover study.

It is typical of night workers to consume a large dinner meal before their work shift, even though this practice may increase the risk for metabolic disorders. Night workers usually eat at night to socialize with colleagues as well as to stay alert and to avoid upset stomach during the night shift. However, little is known if and how the composition of the nighttime meal by night shift workers influences their food perceptions and eating behavior later during the day. The aim of this study was to analyze the effect of a high-protein/moderate-carbohydrate (HP/MCHO) meal vs. low-protein/high-carbohydrate (LP/HCHO) meal eaten at night by night-shift workers on their food consumption and perceptions later during the day. Fourteen male night shift workers were followed-up for 7 days for their eating and sleep habits. Then, participants underwent two isocaloric dietary events - one event a HP/MCHO meal containing 45% carbohydrate, 35% protein, and 20% fat and the other event a LP/HCHO meal containing 65% carbohydrate, 15% protein, and 20% fat, with a 6-day washout period between them - at 01:00 h during their night shift. Thereafter throughout the day, participants filled a food register of all the food consumed and perceptions, including hunger before meals, enjoyment of meals, and satiety. Generalized estimating equation analyses were used to examine the effect of both conditions on food consumption and food perceptions. Appetite for salty food snacks was greater after the HP/MCHO condition than after the LP/HCHO condition (p = .041). During the day following consumption of the nighttime HP/MCHO vs. LP/HCHO meal, there was higher percentage of carbohydrate consumption during lunch and a lower percentage of fat consumption during dinner (48.14% vs. 36.98% and 27.34% vs. 40.39%, respectively). These findings suggest the composition in terms of carbohydrates, protein, and fats of the meal consumed for the night shift by night workers may affect later during the day both food consumption and perceptions.