Effect of Mastication on Satiety Using an Attentional Bias Task

Objectives: Due to the growing obesity epidemic, new strategies are needed to reduce appetite. Mastication has been recognized as an important factor that influences satiety. However, the mechanism by which mastication suppresses appetite is not clear. It has been considered that appetite is associated with an attentional bias toward food in psychological field. The aim of this study was to examine the effect of mastication on appetite using subjective scales and attentional bias tasks.
Methods: Forty-nine healthy subjects (mean age ± SD = 25.8 ± 3.8) were instructed to fast at least 10 hours before the experiment. They were divided into two groups; one group completed a visual probe task (VPT) to measure their reaction time (RT) for assessing attention to food-related visual stimuli, and another group completed an eye-tracking (ET) experiment to measure gaze direction and duration for the food stimuli. All participants rated their hunger on a visual analogue scale (VAS). The VAS and either VPT or ET were performed 1) before and after chewing gum, and 2) before and after eating food on separate days. All of the statistical analyses were conducted at a significance level of 0.05.
Results: Compared with the fasted state, the scores on the hunger scale were significantly lower after chewing gum and eating food. In the VPT experiment, the magnitude of the attentional bias to food images was significantly reduced after chewing gum and eating food. In the ET experiment, the gaze direction and duration biases to food were significantly reduced after eating food. The gaze direction bias was significantly reduced after chewing gum, although no significant change was found in the gaze duration bias.
Conclusions: These results suggest that chewing gum might reduce subjective appetite and attentional bias to food.