Switching to a farming lifestyle was certainly not done by choice, but to avoid death by starvation, as we now know that this has caused various health problems, especially in the beginning, presumably until experience has taught them to achieve a more balanced diet, by combining at least 3 kinds of plant seeds, 2 with complementary amino acid profile and 1 kind of oily seeds for essential fatty acids (the most ancient farming societies have combined barley or einkorn or emmer wheat with lentils or peas or a few other legumes less used today and with flax seeds).
[0] Well, technically in favour of the grain! Pun not initially intended: https://en.wikipedia.org/wiki/Against_the_Grain:_A_Deep_Hist...