Mee Jawa is one of those dishes where the calories sneak up on you. The gravy looks watery but it's thickened with sweet potato and sometimes potato too, so the ~200ml of gravy alone clocks in at 125 calories before you've touched the noodles. Add 150g of egg noodles (180 cal), fried tauhu (80 cal), a hard-boiled egg with bean sprouts (80 cal), and then that cucur udang on top (105 cal by itself), and you're at 570 calories for the full bowl. It's not a disaster, but it's not light either. Fair warning though: hard data on Mee Jawa is thin compared to more famous dishes like char kuey teow, so treat this as a solid ballpark estimate, not a lab result.
What actually swings the number is the gravy and the fritters. Hawker stalls vary a lot in how thick and sweet they make the gravy, and some add a proper spoon of sambal that pushes the bowl closer to 650 calories. Drop the prawn fritter and you're immediately at 450 calories, which is a much more manageable lunch. The protein is decent at 22g thanks to the egg, tauhu and prawns, but if you want to make this a proper high-protein meal, ask for an extra egg instead of the extra fritter. You'll get more satiety for fewer calories, and the stall auntie probably won't even charge you much more.