There's a reason it's become commonplace to grab a cup of coffee first thing in the morning rather than a can of Coke or a cup of tea. Coffee has the most caffeine of the three drinks per volume, with fresh-brewed coffee containing 96 mg per 8 ounces and instant offering 62 mg per 8 ounces. Even decaffeinated coffee still has a trace of caffeine, clocking in at 2 mg per 8-ounce serving. Meanwhile, espresso will give you 64 mg for a 1-ounce serving (via The Mayo Clinic).

Compared to coffee, black tea offers 47 mg of caffeine per 8 ounces, and green tea offers 28 mg per 8 ounces. Like coffee, even the decaffeinated type contains 2 mg of caffeine per 8 ounces. When you're looking for an energizing soda, don't go for lemon-lime citrus drinks to wake you up as they contain no caffeine. However, colas are a different story, offering 22 mg per 8-ounce serving.

Of course, if you really want a jolt to wake you up — or keep you up — you can always go for an energy shot, which will give you a whopping 215 mg of caffeine per 1-ounce serving. Just remember: The Mayo Clinic advises that people drink no more than 400 mg of coffee a day, so an energy shot can give you more than half of what's safe in just a few seconds.