I’m not able to, yet, and I think about it a lot. I’ve been an animal person most of my life, but I tried and failed (ended 2 years ago) to grow my protein by feeding potatoes to my laying ducks. I ended up feeding them mostly grain, so I decided that my current situation to be even 75% self sufficient I would have to be mostly plant based/vegan.
I ate a ton of potatoes, squash, flour corn, tomatoes, greens, and dry beans (bought beans until I get my big bean harvest in this year). But I ended up with low energy, was anemic, gained weight, and the biggest problem–I kept waking up in the middle of the night really hungry and generally had blood sugar issues. Too many carbs for me. I introduced some meat back into my diet, cut all the carbs and I feel back to normal.
This really stinks because I LOVE potatoes, squash, and corn so much and I thought they were the solution to the bulk of my calories 
It will be hard for me just to taste as many squash as I need to continue working on my 5 squash breeding projects lol.
I’m growing a ton of beans this year and making a big effort to learn how to eat them daily (I do not love eating beans, yet) and will trade squash for animal products with neighbors/friends. Lengthy learning process for me for sure.
This book is very cool, originally recommended by Anna
And another discussion about this