Honestly, 500 calories for half a crab sounds almost reasonable for a restaurant dish. But let's be real about what's in there. The actual crab meat, about 120g edible, is only 115 calories. The other 385 calories are butter (180 cal), salted egg yolks (110 cal), and cooking oil (65 cal). You're basically paying restaurant prices to eat fat with a crab-shaped delivery mechanism. That said, 26g of protein is genuinely good, and if you're the type who orders this at dinner and keeps the rest of the day clean, it does fit. This is a treat dish, not a daily lauk. Also worth flagging: these numbers are a ballpark estimate, because there is very little hard nutritional data for Malaysian restaurant dishes like this. The actual calorie count swings a lot depending on how heavy-handed the kitchen is with butter and how big the crab is.
What actually changes the maths is the sauce volume. A hawker stall doing smaller crabs with a thinner sauce coat can land at 380 calories. A restaurant that drowns the crab in thick creamy salted egg sauce and sends you a whole 1kg crab solo is looking at 950 calories. The crab itself barely moves the needle, bro. It's all about how much sauce ends up on your plate. If you're eating this with mantou buns and scooping up every last bit of sauce, you could easily add another 300 calories to your count without realising. The version you order at a Chinese seafood restaurant in KL or Penang is almost always the heavier end. A good rule: eat the crab, go light on the sauce mopping.