Mamak nasi goreng tastes sweet and rich for a reason, there is sugar in the sauce and a good amount of oil in the wok. It is basically a big plate of rice carrying sauce and oil. The egg and the bits of chicken or seafood help, but the protein is low compared to the calorie load, so you are hungry again in a couple of hours.
If you are at the mamak deciding what to order, plain chicken with rice or even a couple of telur beats nasi goreng mamak on protein per calorie. Does not taste as good, I know. But that is the trade.