Ketupat nasi is honestly one of the more innocent things on the Raya table at 145 calories a piece. If you have never had it, picture plain jasmine rice that has been compressed into a firm cube by boiling it inside a woven coconut-leaf pouch. Chewy, dense, mild on its own. The calorie numbers here are a ballpark estimate because hard nutritional data on traditional ketupat is thin, so treat 145 as a reasonable guide rather than a lab-verified figure. The real trap is the glutinous version, ketupat palas, which is cooked with coconut milk inside a palas leaf and comes in at around 210 calories per triangle despite being smaller than a ketupat nasi. Santan does that to things.
What actually wrecks your Raya calories is everything around the ketupat. A serving of rendang alone adds 200 to 300 calories. A ladle of kuah kacang can pile on another 150 to 200 calories depending on how thick it is. If you eat two pieces of ketupat nasi (290 calories) with a proper serving of rendang and kuah kacang, you are already looking at 600 to 700 calories before you touch the serunding or the kuih. The fix is not skipping the ketupat. It is controlling the sauces. One piece with a modest scoop of rendang and lots of acar or raw ulam on the side keeps the meal enjoyable without going totally overboard.