Not all humans were on meat and fat only diet during the last ice age. There is archeological evidence which shows that humans in some parts of the world were consuming wild grains, seeds, nuts, starchy roots and tubers during the last ice age. Not all countries and lands were covered with ice sheet and glaciers...Large parts of the world such as Africa, Middle East and parts of Asia were not covered with ice sheets and humans who lived there at that time ate a variety of plant foods.