I cannot eat sweet bread, because it makes me fat very quickly. )))

As for extra proteins in meat. I don't know from the top of my head, but I can find out if you are interested and will get back with you. I was listening for a lecture from a nutritionist. In the meanwhile, here's something that I found after a quick search

https://www.healthline.com/nutrition/7-nutrients-you-cant-get-from-plants#1