Chewing Stimulation Reduces Appetite Ratings and Attentional Bias toward Visual Food Stimuli in Healthy-Weight Individuals

Abstract

Based on the theory of incentive sensitization, the exposure to food stimuli sensitizes the brain’s reward circuits and enhances attentional bias toward food. Therefore, reducing attentional bias to food could possibly be beneficial in preventing impulsive eating. The importance of chewing has been increasingly implicated as one of the methods for reducing appetite, however, no studies to investigate the effect of chewing on attentional bias to food. In this study, we investigated whether chewing stimulation (i.e., chewing tasteless gum) reduces attentional bias to food as well as an actual feeding (i.e., ingesting a standardized meal) does. We measured reaction time, gaze direction and gaze duration to assess attentional bias toward food images in pairs of food and non-food images that were presented in a visual probe task (Experiment 1, n = 21) and/or eye-tracking task (Experiment 2, n = 20). We also measured appetite ratings using visual analog scale. In addition, we conducted a control study in which the same number of participants performed the identical tasks to Experiments 1 and 2, but the participants did not perform sham feeding with gum-chewing/actual feeding between tasks and they took a rest. Two-way ANOVA revealed that after actual feeding, subjective ratings of hunger, preoccupation with food, and desire to eat significantly decreased, whereas fullness significantly increased. Sham feeding showed the same trends, but to a lesser degree. Results of the visual probe task in Experiment 1 showed that both sham feeding and actual feeding reduced reaction time bias significantly. Eye-tracking data showed that both sham and actual feeding resulted in significant reduction in gaze direction bias, indexing initial attentional orientation. Gaze duration bias was unaffected. In both control experiments, one-way ANOVAs showed no significant differences between immediately before and after the resting state for any of the appetite ratings, reaction time bias, gaze direction bias, or gaze duration bias. In conclusion, chewing stimulation reduced subjective appetite and attentional bias to food, particularly initial attentional orientation to food. These findings suggest that chewing stimulation, even without taste, odor, or ingestion, may affect reward circuits and help prevent impulsive eating.

Feed intake of the sow and playful creep feeding of piglets influence piglet behaviour and performance before and after weaning

“…Thirdly, we predict that the higher frequency of manipulating behaviours on the toys of the play-feeder, such as chewing, might have facilitated the transition from exploratory to eating behaviour (e.g. via stimulation of mastication muscles 60,61 , changes in gut hormone secretion 62 and reward circuits responses 63 or habituation to a dry mouthfeel), but only became evident when their need to consume solid feed increased, either by weaning or maternal feed restriction. Lastly, the provision of play-objects before weaning, thereby eliciting an early play experience for piglets, might also improve their ability to emotionally cope with weaning according to the ‘training for the unexpected hypothesis’ 64 .…”

The Cognitive Control of Eating and Body Weight: It’s More Than What You “Think”

“…In support of her overall analysis, Higgs and colleagues also found that enhancing the encoding of memories of a previous meal by requiring extra chewing reduced subsequent snack intake (Higgs and Jones, 2013). It should be noted that the act of chewing alone, even in the absence of calories, taste, or odors, can suppress appetitive behavior (Ikeda et al., 2018). In contrast, interfering with the encoding of a previous meal by exposing participants to distracting activities (e.g., watching TV, playing a video game) while eating increases subsequent snack intake (Higgs and Woodward, 2009; Mittal et al., 2011; Oldham-Cooper et al., 2011; Higgs, 2015).…”

Aging and neural vulnerabilities in overeating: A conceptual overview and model to guide treatment

“…In addition to protein, there is some evidence that fiber has favorable effects on appetite by slowing digestion and through the release of gut hormones that signal feelings of fullness 64 . Finally, preliminary evidence suggests that consuming water ≤30 min prior to eating a meal reduces caloric intake 65 as does eating solid foods that promote increased chewing 66 . An intriguing hypothesis is that protein and fiber have favorable effects on connectivity across both functional networks that we identified as being associated with weight loss.…”

“…64 Finally, preliminary evidence suggests that consuming water ≤30 min prior to eating a meal reduces caloric intake 65 as does eating solid foods that promote increased chewing. 66 An intriguing hypothesis is that protein and fiber have favorable effects on connectivity across both functional networks that we identified as being associated with weight loss.…”