When I started Yoga over 30 years ago it was clear, a yogini doesn't eat meat. It's possible to survive without doing harm to other creatures. One should live a life full of respect for other creatures on this planet.
There are few rules, but to live a life in peace with others is one of the few rules.
It seems clear that muscles are build of protein. If one wants to get stronger it's recommended to eat protein. I even think that I felt so weak years ago, because my nutrition was not adjusted to my lifestyle of 2 and a half hours of Ashtanga yoga. Some poses didn't improve. I felt too weak. I think now that more protein would have made my life easier.
No matter what sports one wants to do, nutrition is as important as the sportive activity itself.
The asana practice is so demanding in Ashtanga yoga, that it's a must to reflect on what we eat.
In the meantime I know people who don't go to restaurants anymore. In restaurants quantity is important, not quality. If one wants to eat well, one must become a chef.
I go so far to say: An advanced yogini can also prepare delicious and healthy meals.
I analysed my food with that fitbit tracker.