Abstract
Early meal timing and chronotype are associated with lower BMI, but their impact on appetite is poorly understood. We examined the impact of meal timing and chronotype on appetite and food reward. Forty-four adults were divided into early (EC; Morningness-Eveningness Questionnaire (MEQ) score = 55 +/- 5) or late chronotype (LC; MEQ score = 40 +/- 6) and assessed for body mass index, habitual energy intake (EI; three-day online dietary record) and eating behavior traits from the Three-Factor Eating Questionnaire (TFEQ). Participants attended the laboratory after >= 3 h fast on two occasions for early (AM; 8-10 a.m.) and late (PM; 4-6 p.m.) counterbalanced testing sessions in a 2 x 2 design. Appetite ratings and food reward (validated diurnal Leeds Food Preference Questionnaire) were measured in response to a standardized test meal. LC was associated with higher BMI (p = 0.01), but not with EI or TFEQ. The composite appetite score was lower in AM than PM (M-Delta= -5 (95% CI -10, -0.2) mm, p = 0.040). Perceived test meal fillingness was higher in AM than PM and EC compared to LC (p <= 0.038). Liking and wanting high-fat food were lower in AM than PM (p <= 0.004). The late chronotype was associated with greater desire for high-fat food (p = 0.006). To conclude, early meal timing and early chronotype are independently associated with smaller appetite and lower desire for high-fat food.