Honestly, Kuey Teow Soup is one of the more chill choices at a hawker centre if you are trying to lose weight. 330 calories for a full bowl that has noodles, fishballs, meat slices, and broth, that is not bad at all. Compare that to Char Kuey Teow which is double the calories because everything gets fried in lard. The reason this one stays light is the cooking method: it is basically just blanched noodles sitting in a clear bone broth. The fat is only 5g for the whole bowl. Most of those calories come from the 150g of rice noodles at 175 calories. Fair warning though, these are ballpark estimates. Hard data for Malaysian hawker dishes is thin on the ground, and every stall uncle has his own idea of what a normal portion looks like.
What actually moves the number up or down is pretty simple. More noodles is the biggest variable. Some stalls give you a 200g noodle portion instead of 150g and that alone adds 60 to 70 calories. The protein swaps matter too: fishballs at 80 calories per 80g are actually quite lean, but if you upgrade to prawn plus meat, you are probably looking at 90 to 110 calories from protein instead. Toppings are the sneaky one. A drizzle of chilli oil here, a tablespoon of fried shallots there, and suddenly your 330 calorie bowl is closer to 400. The broth itself is only about 20 calories so that is not the issue. The noodles and what sits on top of them is what you should be watching.