Recent research from Japan published in the journal Nutrients has provided information on how chewing tempo influences eating behaviors such as meal duration, number of bites, and number of chews. While it’s long been assumed that slower eating correlates with reduced food intake, objective data on the mechanisms behind this has been limited.
The researchers introduced metronome-paced chewing tempos at 40, 80, and 160 beats per minute (bpm) and observed corresponding changes in participants’ meal duration and oral behaviors. At the slowest tempo of 40 bpm, meal durations increased significantly regardless of sex, indicating that slower chewing results in prolonged mealtimes. Similarly, although 80 bpm and 160 bpm also prolonged meal durations, their effects were less pronounced.
In contrast to the commonly held belief that faster eaters consume more calories, the study found no significant association between meal duration and body mass index (BMI) after adjusting for sex. Instead, meal duration was more closely tied to the number of chews and bites taken.
“While nutritional science is often concerned with food metabolism and absorption and dietary content, there’s limited evidence in Japan on dietary behavior that connects the two. This intrigued me to study eating behavior, which involves gender differences,” explains Iizuka, one of the study's leading researchers.
Sex hormones are known to influence feeding behavior in both animals and humans. Prior studies in rodents have shown that estrogen suppresses food intake, while testosterone and progesterone can stimulate it. In line with this, the present study found that meal duration and number of chews and bites varied by sex. However, chewing tempo remained relatively constant between men and women, aligning with findings that this rhythm is governed by the masticatory central pattern generator (CPG) in the brainstem—a neuronal network responsible for rhythmic jaw movements.
The study does have limitations. The sample size was small and not randomized, and the test meal—pizza—was relatively easy to consume. These factors may limit the generalizability of the results to other foods or populations.
This exploratory study provides compelling evidence that meal duration is significantly associated with the number of chews and bites, not chewing tempo or BMI, and that sex differences influence certain eating behaviors. As dietary interventions evolve, considering both behavioral and physiological factors will be critical to creating effective and individualized nutrition guidance.
Sources: Nutrients, EurekAlert
