510 calories for a claypot lou shu fun is honestly pretty reasonable for a full meal, but you want to know what you're actually eating, kan. The biggest calorie contributor here isn't the noodles, it's the minced pork at 155 calories for roughly 70g. Add in the dark soy, oyster sauce, and cooking oil, and that sauce alone is about 65 calories before you even touch the food. The egg adds another 75. So you're sitting at roughly 295 calories just from the protein and sauce components before you factor in the carbs from the noodles. These are honest estimates because detailed nutrition data for claypot lou shu fun specifically is pretty thin. The 510 figure is a reasonable ballpark, not a lab-tested number.
What actually moves the needle here is portion size and how much oil the hawker uncle uses. A small kopitiam claypot comes in closer to 480 calories, while a bigger restaurant portion with salted fish on top can hit 650 calories easily. That salted fish topping sounds innocent but it's usually deep-fried, so you're adding maybe 120 to 140 calories of mostly fat. The gravy is also worth watching. Some places cook it wetter and saucier, which means more oil and more dark soy soaked into those little rat-tail noodles. If you swap minced pork for prawn and squid, you're looking at around 530 calories because seafood is leaner but still adds fat. The 22g of protein from the standard version is decent though, so at least you're not just eating empty carbs lah.