What caused the human brain to start growing, and what significance did climate change have for nutrition around two Ma ago? Increasing climate fluctuations have changed our ancestors’ environment. The forests by the lakes where they had lived retreated, and the journey to the lake and its food sources (fish, aquatic plants) became longer and more dangerous. Humans had to search for food in the ever-increasing open bush areas of the savannah. Hunger drove them to accept food they had previously not wanted or were unfamiliar with. At some point, he discovered how filling and tasty meat is, and he began to hunt small and larger animals, which sustainably satisfied him and his group and provided them with many micronutrients. Meat was an essential source of energy and an important source of micronutrients. Meat, especially offal, has the highest micronutrient density in relation to energy content. Humans have opened up a new nutritive niche by eating almost anything they could tolerate. This made them independent of the seasons and ensured they had consistently high-quality food. Although the Paleo diet’s health benefits are controversial, regular consumption of moderate amounts of meat is by no means unhealthy. For pregnant women and especially young children, meat is an essential source of micronutrients, especially iron and zinc, and it also contains high-quality protein. Meat can significantly reduce the risk of malnutrition. Studies of contemporary hunter-gatherer populations impressively demonstrate this. The example of older adults today shows the importance of meat and animal products as food. The smaller amount of food consumed with increasing age can best be compensated for by meat when it comes to the supply of micronutrients.