Teh o ais is the drink I switched to and never switched back. Teh means tea, O means no milk, ais means iced. That is the whole thing. No condensed milk, no evaporated milk, which is where basically every other kopitiam drink hides its calories. At 60 calories a glass it costs you almost nothing, and you still get something cold and sweet with your food instead of sitting there with plain water feeling sorry for yourself.
The number moves entirely with the sugar, so it depends completely on who is making it. Some stalls pour three teaspoons, some pour five. Five teaspoons puts you at 85 and you would not taste the difference at that point. These are estimates based on typical hawker sweetness, not lab numbers, so treat 60 as a fair middle.
Here is the maths that actually mattered for me. One teh ais a day for a year is about 55,000 calories. Switch to teh o ais and it is 22,000. That gap is roughly 4kg of body fat a year from changing one word in your order. I am not saying it did all the work, but it was the single easiest change I made in the whole 42kg.