From The Conversation, September 13, 2020.
Humans (and our ancestors) have been processing food for at least 1.8 million years. Roasting, drying, grinding and other techniques made food more nutritious, durable and tasty. This helped our ancestors to colonise diverse habitats, and then develop settlements and civilisations.
Many traditional foods used in cooking today are processed in some way, such as grains, cheeses, dried fish and fermented vegetables. Processing itself is not the problem.