Nasi minyak is kenduri food, which means it is designed to taste good and make you feel celebratory, not to help you hit a calorie deficit. At around 750 calories for a standard plate, it sits comfortably in heavy-meal territory. The rice is the main culprit. It is cooked in ghee, sometimes with added oil, and the fat soaks right into every grain. That 250g of rice alone is roughly 445 calories, compared to maybe 325 for the same weight of plain white rice. Add dalca (120 calories, not bad actually) and one piece of kurma with gravy (185 calories), and you are at 750 before you even reach for the acar or telur on the side. To be honest, these are ballpark estimates because hard calorie data for nasi minyak is thin, and every mak cik cooks it differently. Some use more ghee, some use less, some ladle the kurma gravy very generously. The real number at your cousin's wedding could be anywhere from 680 to 850 calories for a similar-looking plate.
What actually changes the maths here is mostly the rice portion and the gravy situation. If you take a smaller scoop of rice, say 180g instead of 250g, you are already saving close to 100 calories without touching the lauk. The kurma gravy is where hidden fat hides, so if you can ask for less gravy and more meat, you get more protein per calorie which is the better trade. Dalca is actually the friend here, it is lentil and vegetable-based and only around 120 calories for a decent scoop. Load up on that instead of asking for extra rice or another piece of meat with heavy gravy. And obviously, if you eat nasi minyak once a year at a wedding, bro, just eat it and enjoy. This is not the meal that broke your diet. The problem is when you eat it every weekend at a kenduri season.