More than 80 percent of American adults consume caffeine regularly. That’s no surprise, what with a coffee shop seemingly on every corner and in every supermarket, and tiny $3 bottles of 5-hour Energy popping up like mushrooms wherever there’s a checkout counter. It turns out, though, that there is also caffeine in ice cream and frozen yogurt.

How does caffeine work in the body?

Caffeine works mainly by temporarily binding to adenosine receptors in the brain. That prevents adenosine, which is a natural sedative produced by the brain, from occupying those receptors and making us feel drowsy. Adenosine levels build up during waking hours and then drop as we sleep.

People who don’t use caffeine regularly and who haven’t developed a dependence on it “usually become significantly more alert and better able to perform cognitive and motor tasks – such as paying attention during boring tasks or typing – if they’re given the right dose of caffeine,” says Laura Juliano, a professor of psychology at American University in Washington, D.C.