Only if it _needed_ a larger brain to get that cooked food. Humans feed cooked food to ourselves, and our big brain helps us to discover and remember new sources of food, and how they need to be treated to become edible (e.g., https://en.wikipedia.org/wiki/Cassava#Toxicity). Without this pressure it’s hard to see how plentiful, nutritious food would do anything other than make the animal sedentary, slow, and stupid (e.g., to one degree or another, koalas, sloths, gorillas, modern humans).