Gum

From tree resin and paraffin wax to Juicy Fruit, people have chewed gum (or gum-like substances) for thousands of years. So it makes sense there's more to the habit that fresh breath or a little masticatory diversion. A lot more, it turns out.

Chewing gum can boost your mood and alertness while combatting stress. That's according to several recent studies, including one 2009 effort from Australian and UK researchers. "There is evidence that chewing increases blood flow to the brain, and this may contribute to the increase in alertness that is consistently associated with gum chewing," says Dr. Andrew Scholey, co-author of that 2009 paper and director of the Centre for Human Psychopharmacology at Australia's Swinburne University . In terms of gum's mood-elevating anti-stress powers, Scholey says chewing the stuff seems to reduce your levels of the stress hormone cortisol. Another study, this one from a team at Eastern Illinois University, found gum helped high school students relax while taking the ACT. But exactly how gum pulls all of this off is still a bit of a mystery.

One possibility: Research shows your stress tends to spike when you're feeling peckish. (It's one of the reasons some people get "hangry" between meals, experts say.) Chewing gum may temporarily turn off some of your brain's stress-elevating "I need food" alarms, and so it may help lower worry and improve calm.

But when it comes to gum and your diet, things get tricky. While some people swear gum helps them cut back on snacks and at mealtimes, chewing certain flavors of gum at the wrong time may be problematic for people hoping to eat healthier. According to a study from the University at Buffalo,c That study's author, Dr. Jennifer Temple, jokingly refers to this as the "brushing your teeth before eating fruit" effect. She explains, "For some people, mint makes fruit taste awful."

Temple's experiments also showed people who chewed gum frequently ate fewer meals than non-chewers-but tended to load up on calories when they did eat. While many

interpreted this as proof that gum isn't an effective diet aid, Temple says her experiments only included mint gum, and put some burdensome restrictions on the gum chewers' eating behaviors, such as forcing them to chew a piece 15 minutes before every meal.

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