Trying to cut down your coffee consumption because you drink too much caffeine? Well, you might be surprised to learn that some soft drinks can pack a pretty big jolt themselves. Which soda do you think packs the bigger buzz? A cola like Coke or the citrus drink Mello Yello?

“The Coke actually has 16 milligrams per 12-ounce can less caffeine than the Mello Yello," says Delia Hammock, R.D., Nutrition Director, Good Housekeeping Institute. "Researchers at Auburn University looked at 131 brands of soda and they found that overall, citrus drinks have more caffeine than colas.”

Sometimes it’s hard to find out just how much caffeine is in sodas. “Manufacturers don’t have to tell consumers on the label how much caffeine is in the soda. Now, Coke and Pepsi do, but many others don’t,” says Hammock.

Which of these colas has more caffeine? Walgreen’s or Sam’s Cola from Wal-Mart? “Walgreen’s Cola has about 39 milligrams of caffeine per 12 ounces, but that’s about three times as much as the Sam’s Cola from Wal-Mart. Generally, brand-named colas have between 33 and 48 milligrams of caffeine per 12-ounze can. But if I go to Starbucks and get a 12-ounze cup of coffee, that’s going to deliver about 260 milligrams of caffeine,” Hammock explains.

A final note: A recent study from Johns Hopkins found that only eight percent of people could tell whether caffeine was even in a soft drink. For more information on Good Housekeeping's caffeine quiz, check out the February issue of Good Housekeeping. And if your favorite soft drink doesn’t list its caffeine content on its label, you can find the score at www.goodhousekeeping.com/caffeine.