Okay so at 350 calories for a plate of Chee Cheong Fun, this is not bad on its face. The noodles are basically just rice and water, so the rolls themselves are 215 calories for 200g. The issue is the toppings. That sweet sauce (tim cheong, a sweet soy-based sauce) clocks in at 55 calories for 30g, and then the fried shallots and sesame seeds add another 65 calories for about 15g. That is 120 calories of pure coating before you even look at the noodles. Protein is only 8g, which means this is mostly a carb meal. Fair warning: these numbers are a ballpark estimate. Hard nutritional data for Malaysian hawker food is thin, so treat this as an educated guess, not a lab result.
What actually moves the maths here is the sauce and the style. KL sweet sauce style at 350 calories is the baseline. Switch to Ipoh or Penang style with curry gravy and wet prawn paste, and you are already at 420 calories because the gravy is fat-heavy. Add three or four pieces of fried yong tau foo on top and you are at 500 calories, but honestly at that point your protein goes up too (probably 18 to 20g), so it is a better trade-off if you are watching macros. The lighter move is to ask for less sauce. In KL most hawkers just drown the thing, so asking for light sauce on the side actually saves you close to 40 to 50 calories without killing the taste.