Why what you eat matters more than how you eat it

In a society facing rising obesity rates, it is more important than ever to find simple and practical ways to encourage healthier eating habits. One common suggestion for supporting digestion and weight control is to eat slowly. However, many people still find it challenging to incorporate this practice into their daily lives. To overcome this struggle, a team of researchers led by Professor Katsumi Iizuka from Fujita Health University, Japan, offered a clear and simple answer, stating that the type of meal we choose may matter more than the order in which we eat it. This study was published in Volume 17, Issue 9 of the journal Nutrients on May 3, 2025. “Eating slowly is widely recommended for obesity prevention,” said Prof. Iizuka. “But people often don’t know how to implement this advice. Our study shows that simply choosing the right type of meal—such as a bento instead of fast food—can naturally extend meal duration and encourage more mindful eating.” The research was also actively supported by Kanako Deguchi from the Department of Clinical Nutrition, Fujita Health University.

The team studied 41 adults (18 males and 23 females, aged 20 to 65) who consumed three test meals over several weeks: pizza, a hamburger steak bento eaten with vegetables first, and the same bento eaten with vegetables last. Researchers used a wearable chewing sensor and video analysis to measure each participant's meal duration, number of chews and bites, and chewing tempo. The findings were striking. Participants ate pizza significantly faster than bento, with shorter meal durations and fewer chews, regardless of whether vegetables were eaten first or last. In contrast, the bento meals—consumed with chopsticks and consisting of individual components like rice, vegetables, and meat—promoted longer meal times and more chewing. Surprisingly, the number of bites remained consistent across meal types, and chewing tempo showed only slight but statistically significant differences.

The study also looked at differences between men and women and found that men generally ate faster and chewed less than women. However, the overall trend was the same in both groups—bento meals took longer to eat and required more chewing. Older participants tended to eat faster than younger ones, which could be due to changes in dental health or chewing ability. One might expect that individuals with a higher body mass index (BMI) would eat faster, but the study found no association between BMI and meal duration, challenging common stereotypes. Instead, the researchers suggest that people with obesity may gravitate toward ultra-processed, easy-to-eat foods like pizza, which could lead to faster meals and overeating.

Prof. Iizuka explains, “One key factor affecting meal speed is how the food is served and eaten. Bento meals are served in small portions that need to be picked up with chopsticks, which slows down the process. In contrast, pizza is eaten by hand and is often designed to be eaten quickly. This difference in serving style plays a big role in how fast people eat.”

Scientists also point out that chewing tempo, or how fast people chew, is controlled by the brain’s natural rhythm and is less likely to change. However, the number of chews and the time spent chewing can vary based on the meal type. Eating slowly by taking more chews and smaller bites helps extend the meal duration, which is linked to better digestion and weight control. “If we want to help people eat more slowly, we should focus less on telling them how to chew and more on helping them choose meals that require slower, more deliberate eating; this could be a simple yet powerful tool in our fight against obesity and related diseases,” says Prof. Iizuka.

In conclusion, this study highlights that making simple meal choices—like opting for traditional bento-style meals over fast food—can naturally slow down eating, increase chewing, and support healthier habits. As obesity rates continue to rise, focusing on what we eat, rather than just how we eat, may be a practical and effective step toward better nutrition and long-term well-being. Simple habits like these could make a big difference in promoting healthy eating behaviors.

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Reference

Title of original paper: The Meal Type Rather than the Meal Sequence Affects the Meal Duration, Number of Chews, and Chewing Tempo

Journal: Nutrients

DOI: 10.3390/nu17091576

About Fujita Health University

Fujita Health University is a private university situated in Toyoake, Aichi, Japan. It was founded in 1964 and houses one of the largest teaching university hospitals in Japan in terms of the number of beds. With over 900 faculty members, the university is committed to providing various academic opportunities to students internationally. Fujita Health University has been ranked eighth among all universities and second among all private universities in Japan in the 2020 Times Higher Education (THE) World University Rankings. THE University Impact Rankings 2019 visualized university initiatives for sustainable development goals (SDGs). For the “good health and well-being” SDG, Fujita Health University was ranked second among all universities and number one among private universities in Japan. The university became the first Japanese university to host the "THE Asia Universities Summit" in June 2021. The university’s founding philosophy is “Our creativity for the people (DOKUSOU-ICHIRI),” which reflects the belief that, as with the university’s alumni and alumnae, current students also unlock their future by leveraging their creativity.

Website: https://www.fujita-hu.ac.jp/en/index.html

About Professor Katsumi Iizuka from Fujita Health University

Professor Katsumi Iizuka is a leading expert in clinical nutrition at Fujita Health University in Japan. He earned his medical degree from Osaka University in 1993 and completed his Ph.D. in 2000. His research focuses on metabolic diseases, including obesity, diabetes, and insulin resistance, with a particular interest in the role of carbohydrate-responsive element-binding protein (ChREBP) in nutrition-related disorders. With over 95 publications and more than 3,000 citations, Professor Iizuka's work significantly contributes to understanding the nutritional factors influencing metabolic health and disease prevention.

Funding information

This research received funding from the Suzuken Memorial Foundation (23--003).