190 calories for a drink sounds okay until you realise you're ordering two of these with your nasi lemak and roti canai. The calories here come from both the rose syrup and the evaporated milk, and they contribute almost equally: about 90 calories from the syrup and 95 from the milk. Rose syrup alone is 90 calories for just 55g, which is basically cordial with red dye. Add evaporated milk at 95 calories per 100g and you've got a proper calorie bomb in a glass. The ice and water dilution save you a bit, but not enough to pretend this is a light choice. If you're counting, 190 calories for a drink is the same as a small bowl of plain rice, lah.
What actually changes the number is how heavy-handed the uncle is with the syrup and milk. Some hawkers go really generous with both, which can push this to 220 or even 250 calories easily. The soda version (Bandung Soda) swaps some of that evaporated milk for soda water or sarsi, bringing it down to around 160 calories, but the sugar stays roughly the same because the syrup doesn't change. If you're trying to cut calories without giving up the drink entirely, ask for less syrup, get the soda version, or just drink half and leave the rest. Both the syrup and the milk contribute roughly equally here, so cutting back on either one will make a real difference.