Lala are small saltwater clams and this dish is a Malaysian hawker staple. You order a plate, you get a heap of shells, you dig out the little nuggets of clam meat and you mop up the sauce with whatever carbs you ordered alongside. The clam meat itself is genuinely low calorie and high protein, very similar to other shellfish. The 250 calories here is a ballpark estimate, honestly, because reliable nutrition data for hawker-cooked lala is thin. Different stalls use wildly different amounts of oil and sauce, so treat this as a reasonable middle-ground guess rather than a precise number.
What actually swings the calories up or down is the oil. The hawker version uses around 1.2 tablespoons of oil in the wok, which contributes about 136 of those 250 calories. Kam Heong lala, which adds dried prawns, curry leaves and more sauce, runs closer to 300 calories. Sambal lala pushes to around 320 because sambal paste is oil-heavy by nature. The halia version with ginger and spring onion is the lightest at about 220 calories because the sauce is simpler and the oil tends to be more restrained. If you are eating lala as a side to white rice, the lala itself is not your problem. Watch the rice portion and whatever sauce you pour over it.