Legumes tend to be very filling for the amount of protein they provide, plus having to complement them with grains to make a complete protein greatly increases the Calories to protein ratio. Rice and beans do make for a great cheat meal when you can fit it in though.
I’ve never heard of needing to add grains to make a complete protein. What does that even mean?
Proteins are made from amino acids, same as words are made from letters. If you eat a protein source that’s short on some of those letters then you need to mix it with a source that has more of them… Otherwise you can’t create all the proteins that you need. (It’s a bit more complicated, but that’s the bit that you need here)
yes, iirc Quinoa is pretty good complete vegan protein other pulses and grains not so much.
You didn’t really need to, if you are not in a heavily restricted diet. Adam Ragusea has a nice video about this: https://youtu.be/psAlJtgeQsY
IIRC, his point was just that it doesn’t have to be in one meal. Your diet as a whole still needs all the amino acids.