Value Village ／ Health
This answer is a draft. It stays unpublished until legal review and source verification are complete.
"Chew each mouthful 30 times" is a rule repeated in Japanese food education (*shokuiku*), and people from abroad often ask whether it really means anything. Here we look at how the number of chews has changed over history, and at what public sources allow us to say.
| Item | Detail | Source |
|---|---|---|
| Chews per meal (estimate) | Pre-war about 1,400 → today about 600 | Estimates in dentistry and nutrition science (research by Shigeru Saito and others) |
| Guide | 30 chews per mouthful ("Kaming 30" (噛ミング30, *kamingu sanmaru*), since 2009) | MHLW |
| 8020 campaign | Keep 20 of your own teeth at age 80. About half of people achieve it (2022 Survey of Dental Diseases) | MHLW, Japan Dental Association |
| Saliva | 1–1.5 L a day. Chewing increases the flow, which works for digestion, cleansing and neutralising acid | General physiology |
| Fast eating and obesity | Several Japanese studies find a higher risk of obesity among fast eaters | Studies linked to the National Health and Nutrition Survey |
[Verify] The chew-count figures are researchers' estimates. Check the 8020 achievement rate against the latest Survey of Dental Diseases, and Kaming 30 against MHLW material.
Chewing breaks food down and lets the enzyme in saliva (amylase) start working. Swallowing food whole is generally described as a burden on the stomach and gut.
Counting is not the point; choose foods that need chewing and the number rises by itself. Root vegetables, mushrooms, seaweed, brown rice, and cutting food into larger pieces are the tricks used in Japanese food education.
For chewing strength, the jaw and saliva, fewer chances to chew are generally described as a disadvantage. For older people too, a diet that needs chewing, for as long as they can chew, is recommended to maintain oral function.
Research shows that fast eating delays the feeling of fullness, so the amount tends to rise. There are also reports that eating the same amount slowly is more satisfying.
Chewing produces saliva that washes the mouth, and stimulates the tissues around the teeth. That is why the 8020 campaign has "keeping teeth you can chew with" as its goal.
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https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/kenkou/shika/
https://www.mhlw.go.jp/toukei/list/62-17.html
https://www.e-healthnet.mhlw.go.jp/information/food/e-02-010.html
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
Please decide for yourself, using your own judgement, whether any of this suits your situation. We cannot accept responsibility for any damage, loss or injury arising from following this article.
This article is not meant to diagnose or manage any specific medical condition. If you are worried about your health, see a doctor rather than relying on your own judgement.
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