Genesis tells us that Adam, Eve and all animals had originally plant-based diets, as God provided them with every plant and tree for food:
29 And God said, “Behold, I have given you every plant yielding seed that is on the face of all the earth, and every tree with seed in its fruit. You shall have them for food. 30 And to every beast of the earth and to every bird of the heavens and to everything that creeps on the earth, everything that has the breath of life, I have given every green plant for food.” And it was so. 31 And God saw everything that he had made, and behold, it was very good. And there was evening and there was morning, the sixth day. [Genesis 1:29-31, ESV]
However, later passages of the Bible reveal that, after the fall, God approved of animal-based diets:
And God blessed Noah and his sons and said to them, “Be fruitful and multiply and fill the earth. 2 The fear of you and the dread of you shall be upon every beast of the earth and upon every bird of the heavens, upon everything that creeps on the ground and all the fish of the sea. Into your hand they are delivered. 3 Every moving thing that lives shall be food for you. And as I gave you the green plants, I give you everything. [Genesis 9:1-3, ESV]
9 The next day, as they were on their journey and approaching the city, Peter went up on the housetop about the sixth hour to pray. 10 And he became hungry and wanted something to eat, but while they were preparing it, he fell into a trance 11 and saw the heavens opened and something like a great sheet descending, being let down by its four corners upon the earth. 12 In it were all kinds of animals and reptiles and birds of the air. 13 And there came a voice to him: “Rise, Peter; kill and eat.” 14 But Peter said, “By no means, Lord; for I have never eaten anything that is common or unclean.” 15 And the voice came to him again a second time, “What God has made clean, do not call common.” 16 This happened three times, and the thing was taken up at once to heaven. [Acts 10:9-16, ESV]
22 “But the father said to his servants, ‘Quick! Bring the best robe and put it on him. Put a ring on his finger and sandals on his feet. 23 Bring the fattened calf and kill it. Let’s have a feast and celebrate. 24 For this son of mine was dead and is alive again; he was lost and is found.’ So they began to celebrate. [Luke 15:22-24, ESV]
Question: Why did God eventually sanction animal-based diets after the fall if originally the norm across the board was veganism? Was it for nutritional reasons or something else?
I don't know if there is a unique answer to this question, so I'm posing it as a request for an overview of Christian viewpoints. Obviously, my intention is not to overwhelm you with a question that is impractically broad, so it would be just fine for me if an answer is posted simply enumerating some of the most compelling views according to e.g. a reputable Christian authority on the matter, etc.
Update based on the comments:
Answers can include viewpoints that reject the premise (that veganism was the norm right after Creation and before the Fall), I have no issues with that, as long as quotes or summaries of the argumentations given to reject the premise are included.
To those who reject the premise: you guys have inspired to ask a related question on Hermeneutics.SE: Does Genesis 1:29-31 leave any room for the existence of animal-based diets in the period between the Creation and the Fall?. Feel free to explain your reasons on that question.