It used to be meat, and then that was corrected to be starch (potatoes are easy to farm and store)
But there are other starches too.
Just think what the world could have been like if not for the environmental devastation of the 16th century. ;D
On the other hand I don't think that this must be a one-factor kind of a game changer thing. I could totally think that two to three changes occured in the food chain (meat, starches, food preservation, improved social skills), that combined amplified each other's effect and lead to the development.