Calvin from the comic strip Calvin and Hobbes used to read a special interest magazine about gum called Chewing, which, according to the Calvin and Hobbes Wiki, contained articles on cultivating a "mandibular fitness regime," for a stronger jaw. As an avid chewer, perhaps Calvin was right to be concerned about his jaw’s resilience—a recent study from Tel Aviv University, published in Pediatric Neurology shows an association between “excessive gum-chewing” and chronic headaches in adolescents.

The researchers cite a recent survey that found that 84 percent of high school students suffered from recurring headaches. They note that “very little has been reported in the literature on gum-chewing as a potential trigger [for headaches]: one report pertains a single case attributed to excessive gum-chewing, whereas another study described three adults whose headaches were considered to be associated with the sweetener aspartame present in the gum.”

So, to test the theory, they recruited 30 adolescents with chronic headaches who said they chewed gum daily. The participants were divided into categories based on how much time they spent chewing every day: up to one hour, one to three hours, three to six hours, or more than six hours per day. (Who is chewing gum more than six hours per day?? That’s actually chewing gum like it’s your job.)