Ketam Masak sits at around 300 calories for a standard hawker serving of half a crab with sambal sauce, and honestly that is not bad at all for a lauk. The crab meat itself is only about 70 calories for 70g, which makes it one of the leaner proteins you can order. The problem is the 15g of cooking oil the hawker uses for that high-heat wok fry, which alone contributes roughly 130 calories. Add in the sambal paste at about 80 calories and you have a dish where the sauce costs you more than the protein. Fair warning though, these numbers are a ballpark estimate. Hard nutrition data for Malaysian crab dishes is thin, and every hawker cooks differently, so treat 300 calories as a reasonable middle-ground figure, not a lab result.
What actually changes the maths is the variant you order and how much gravy you eat. Masak Cili is the lightest at around 280 calories because it is drier with less oil. Masak Lemak jumps to 380 calories because santan (coconut milk) is basically liquid fat. And Masak Telur Masin? That one hits 450 calories because butter and salted egg yolks all pile in at once. The other big variable is portion size. If you are at a restaurant and they give you a full crab instead of half, double everything lah. Eat the crab meat, go easy on mopping up the sauce with your rice, and you will be fine. At 22g of protein per serving, this is actually one of the better protein-per-calorie options in the lauk lineup.