Sate lilit is minced meat, not chunks, and the mix is roughly two parts fish to one part grated coconut. That coconut is the reason a 20g skewer is 51 calories with 64% from fat. Plain grilled fish of the same weight would be about 25. So it is not a lean protein snack, it is a moderately fatty one, but 5 skewers still gives 20g protein for 255 calories, which is fine.
Portion is the question. Warungs sell it by the stick at Rp 3,000 to 5,000, and a normal side order is 5. At a nasi campur stall you get 2 on the plate, about 100 calories. At a beach restaurant the 'sate lilit set' with 10 skewers, rice and sambal matah is around 700.
Pork sate lilit (babi) is fattier than fish (ikan) or chicken (ayam), about 65 per skewer rather than 51, because pork mince already has fat before the coconut goes in. Tuna or mahi-mahi lilit is the leanest, and it is what most tourist-area warungs use.
It is grilled over coconut husk charcoal with no sauce, so what you see is what you get. There is no peanut sauce pour like Javanese sate, which is why 5 lilit at 255 beats 5 sate ayam with sauce at about 300.