What is Fletcherism promoted by businessman Horace Fletcher?

It was the theory promoted by late 19th-century businessman Horace Fletcher that extensive chewing, or “mouth thoroughness,” would improve one’s health.

In such books as Fletcherism: What It Is and The ABC of Nutrition, Fletcher said that every bite of food should be chewed 32 times to “give every tooth of mine a chance.”

Among Fletcherism’s practitioners were Thomas Edison, John D. Rockefeller, and Upton Sinclair.