Bro, bubble tea is not a drink, it is a dessert you sip through a fat straw. The tea part is almost nothing. It is the pearls and the sugar that do all the damage. Those chewy pearls are pure starch soaked in syrup, so a normal scoop is 150 calories just sitting at the bottom of your cup.
Then they ask you sugar level and most people just say normal, which is full sugar lah. Full sugar plus pearls plus non dairy creamer and you drank a small meal. One a day, every day, that is 2660 calories a week you did not chew. No wonder the weight does not move.