The sweetest drinks in the US: These bestselling beverages have the most sugar per ounce

Quenching summer's heat with a sugary soda or lemonade seems quintessentially American.

But many people don't understand how sweet their favorite drinks really are.

The World Health Organization recommends that adults limit themselves to 25 grams of added sugar per day. The US Food and Drug Administration (FDA) is more generous with its guidelines, suggesting Americans consume no more than 50 grams of sugar daily.

The average American, meanwhile, consumes nearly double the FDA's limit - and scientists are increasingly discovering the dire consequences of such excess.

To see where America is getting its sugar, Business Insider asked Euromonitor to provide data on the bestselling non-diet drinks in the US in six categories: colas, non-cola sodas, coffees, teas, energy drinks, and energy shots. We then looked up the sugar content and drink volume using CaffeineInformer.com.

As the chart below shows, colas and other sodas are a huge contributor to US sugar intake, but they aren't the only drinks to blame. We ranked the beverages based on their sweetness, or grams of sugar per fluid ounce. Each one's total sugar level is also shown in sugar cubes. (One sugar cube weighs about 2.3 grams.)

The results show that incredibly sweet drinks can come in very small containers.

For example, even though a Red Bull contains less sugar than a Starbucks Grande Caffe Latte Mocha, it's 155% sweeter per fluid ounce (even though a Red Bull is about half as big). On the other hand, if you're getting your caffeine kick from a Rockstar energy drink, it may help to know it's 118% sweeter than a Red Bull.

This analysis, however, only covers the most-sold drinks in America. The all-out winner for "sweetest American standalone drink" seems to be Screamin Energy Max Hit, which has 9 grams of sugar packed into every 0.6 fluid ounces. This makes it - ounce for ounce - 386% sweeter than Mountain Dew, the sweetest drink on our list of US bestsellers.