Legend has it that a teahouse manager in Taiwan, bored during a long meeting, dumped tapioca pudding into an iced tea, decided it actually tasted pretty good, and added her concoction to the menu. The new tapioca tea became their biggest seller, and a trend was born, spreading throughout Taiwan and beyond. Now bubble teashops are cropping up all over the world, offering flavors ranging from lychee and kumquat to red bean matcha and coconut milk tea.

Bubble tea--also known as boba tea or milk tea--is typically made by adding a scoop of black tapioca “pearls” to the bottom of a cup, pouring in cold green or black tea, and mixing in fruit juice, fruit puree, chocolate, milk, and other flavorings. It’s vigorously shaken (the “bubbles” in bubble tea actually refer to the bubbles that form when it’s mixed) and served with a wide straw that allows room for the pearls to be sucked up along with the tea. You drink the tea, then chew the pearls.

Because it’s a tea-based drink, bubble tea has earned something of a health halo. After all, tea--especially green tea--is known for containing disease-fighting compounds. Tea is rich in natural plant chemicals called polyphenols, which may help reduce inflammation and act as antioxidants in the body, shielding cells from damage.

Not to burst anyone’s bubble, but just like calorie-packed menu items at coffee shops, bubble tea can be more like a dessert than a drink. Though the tea itself is naturally very low-calorie, some of the concoctions pack a hefty amount of added sugar thanks to ingredients like fruit juices and flavored syrups. The pearls--sweet, chewy balls made from the starchy cassava root--add more than 200 calories per half-cup. And bubble tea portions can be just as oversized as venti mochas. A large tiramisu bubble tea at my local shop clocks in at more than 500 calories.

Speaking of health concerns around bubble tea, I should also mention that there have been rumors that the signature tapioca pearls contain potentially harmful chemicals. Several years ago, researchers from Germany identified chemicals in the pearls that were mistakenly labeled as PCBs, a class of compounds that may be cancer-causing. But according to University of California Berkeley, this has since been disproven. The compounds in the tapioca are actually chemicals used in food flavorings and are approved for use by the FDA.

If you’ve caught the bubble tea bug and want to lighten up your drink, there are a few things you can do: Most shops let you choose your level of sweetness (including unsweetened), so opt for a lower sugar level than the default. Ask for regular milk instead of sugary creamers or sweetened condensed milks. You could also go pearl-free--or light on pearls--to save 100-200 calories. Check menu boards for calorie counts and sip (and chew!) on the lighter drinks more often than the indulgent picks. And stick to the smallest size, which is typically already generous.