Recently, in a book by a gastroenterologist, I found very specific suggestions about how many times we should chew our food:

chew softer foods 5-10 times per mouthful and denser foods like meats and raw fruits and vegetables up to 30 times before swallowing.

    The book provided a reference to support this. This surprised me, because I did not know that anyone had formally studied food chewing. I decided to double check the references. Here’s what I found.

    The abstract of the referenced article did not discuss how many times to chew different types of food. Instead, it described a study where participants chewed pizza either 15 chews or 40 chews per mouthful. Those who chewed more ate less pizza. I looked for an interview or article where the authors made specific suggestions, without success.

    The book also mentioned that researchers at the University of Manchester found that chewing food releases helper T-cells in the mouth that can fight infection. The book did not provide this reference, but I found an article that did indeed support that, based on studies in mice.

    However, in interviews, the investigators were on the fence about whether extra chewing was good or not. More chewing can contribute to bone loss in periodontal disease, they said, also based on studies in mice. It’s hard to know whether the increase in helper T-cells or the bone damage would happen in people.

    I then consulted that modern-day oracle, the artificial intelligence tool ChatGPT. I asked it how many times I should chew my food before swallowing. Here is its reply:

The number of times you should chew your food before swallowing can vary depending on several factors including the type of food, your dental health, and your digestive system. However, a general guideline is to chew your food thoroughly until it reaches a consistency that is easily swallowed and digested. This usually means chewing each bite around 20 to 30 times. Chewing your food thoroughly helps to break it down into smaller particles, which aids in digestion and nutrient absorption. Additionally, it can also help prevent issues such as choking and indigestion. However, it's important to listen to your body and adjust chewing times as needed based on your own comfort and digestion.

    When asked for references on the subject, ChatGPT gave me website addresses for the expert opinions of various foundations and governmental agencies. When asked for scientific articles, it provided a couple of review articles, but also equivocated:

These articles may not directly address the specific question of how many times one should chew food before swallowing, as this can vary based on individual factors such as the type of food, personal chewing efficiency, and dietary needs.

    I’ll also add that I used ChatGPT twice, and the first time, when asked for references, it provided some that were irrelevant or nonexistent.

    Why am I telling you all this? Had I taken the book by the gastroenterologist at face value, I would be passing along advice about how many times to chew your food. Some of you would then start earnestly chewing away. But the reality is that there is no solid data about how much you should chew.

    This is a relatively trivial point. But I have been amazed, in reading both scientific literature and lay literature, how many times the reference does not support the point made. While I don’t double check everything in every article, I do double check when the issue is important.

    And finally, how much should you chew? I agree with the answer ChatGPT gave, with the caveat that I don’t think there is solid research to support the “20 to 30 times.” Perhaps someday, someone will perform such a study, but for now, we must rely on common sense.