Greater Numbers of Chews and Bites and Slow External Rhythmic Stimulation Prolong Meal Duration in Healthy Subjects

Background/Aim: Slow eating is recommended for obese individuals. We aimed to determine the associations between meal duration and various factors (sex, numbers of chews and bites, eating tempo (including forced rhythm with a metronome) and BMI). Methods: Using a test meal (a quarter slice of pizza), we tested the sex difference of the meal duration, numbers of chews and bites, and eating tempo for thirty three healthy subjects (M: 15; F: 18) aged 37.2 ± 11.1 years via unpaired t tests. Next, factors influencing meal duration were identified via multivariate analysis (adjusted for sex), with meal duration as the dependent variable. Results: The meal duration and numbers of chews and bites differed significantly between sexes (63.1 ± 20.7 vs. 87.4 ± 22.8, p = 0.003; 80.3 ± 28.7 vs. 107.0 ± 36.1, p = 0.02; 2.1 ± 1.1 vs. 4.5 ± 2.6, p = 0.001, respectively), but the chewing tempo was similar (p = 0.32). Meal duration was associated with the number of chews (β = 0.6 [0.4, 0.7], p < 0.001) and bites (5.8 [2.5, 9.2], p = 0.001) but not with BMI (p = 0.52) or chewing tempo (p = 0.99). Finally, when a metronome was used to force rhythmic stimulation (0/40/80/160 bpm), compared with 0 bpm, slow stimulation (40 bpm) resulted in increased meal duration (mean difference [95% CI] = −47.0 [−66.4, −27.7], p < 0.0001), chews (−28.6 [−44.5, 12.8], p = 0.0003), and bites (−4.9 [−7.9, 1.9] p = 0.001) and delayed tempo (10.4 [4.5, 16.3], p = 0.0004). Conclusions: Meal duration was positively associated with the numbers of chews and bites and negatively associated with chewing tempo. Thus, increasing the numbers of bites and chews and slowing the eating tempo may prolong meal duration.