The banana is the healthy part and it is a third of the calories. A saba banana is about 120 calories per 100g, so the 60g piece inside a turon is about 70. Then it gets a lumpia wrapper (35 calories), a roll in brown sugar that melts into a shell (about 12g, 50 calories) and a trip through hot oil, where the wrapper soaks up about 7g of oil (65 calories). Panlasang Pinoy's recipe card comes out at 292 per piece, but that counts a cup and a half of sugar across 12 pieces as all sticking.
The vendor's sugar habit is the variable. Some carts roll lightly and the shell is thin, about 200 calories per piece. Others dredge heavily and then drizzle more syrup on the finished turon, which pushes it to 280. The jackfruit strip adds about 15 calories and a lot of flavour, so it is not the thing to worry about.
Turon is sold in pairs for 25 to 30 pesos and eaten as merienda, usually with a soft drink. Two turon and a Coke is about 580 calories at 4pm, which is bigger than a lot of people's dinner. The turon with ice cream at restaurants (turon a la mode) is about 370 for one piece with a scoop.