Sago't gulaman is brown sugar water with chewy things in it, and the calories follow the sugar. A vendor ladles about 40g of arnibal (brown sugar boiled with water and a drop of banana extract) into a large cup, which is 150 calories. The sago pearls are cooked tapioca starch, about 30g at 35 calories. The gulaman is agar jelly set with a little sugar, about 40g at 10 calories. Then ice and water to the top. Kawaling Pinoy and Panlasang Pinoy both land around 250 per serving, with a cup of sugar for 6 servings.
The cart drinks are all the same sugar in different colours. Melon juice, buko pandan, black gulaman, the sago't gulaman with a squeeze of calamansi: 150 to 250 per large cup, and the difference is mostly how heavy the vendor's hand is. A large cup is about the same as a can of Coke (140) plus a bit, and people drink 2 in an afternoon because it is 20 pesos and it is hot.
The mall versions with cream or condensed milk are a step up. A large buko pandan with cream is about 280, and the 'special' sago't gulaman with extra sago and a milk float is around 300. Sago't gulaman is a fine drink to have instead of a soft drink, but it is not water with jelly in it. It is 49g of carbs, all of it sugar and starch.