The evolution of Homo as habitual consumers of inside- (marrow, brains) and outside-bone (meat, liver, fat) nutrients within grassland ecosystems, coupled with the infrequency of cardiometabolic diseases in modern hunter-gatherer communities, suggests that ancestral-type diets (although variable) offer insights into what constitutes suitable nutrition. The Neolithic era, characterized by a settled human lifestyle, brought dietary shifts based on crop and livestock agriculture. While presenting novel feeding possibilities, cereal-dominated diets often led to malnutrition, partially mitigated by secondary animal source foods (e.g. dairy). Technological advancements in industrializing societies brought widespread availability of animal-source foods, improving nutrition. However, industrialized diets eventually contributed to so-called ‘diseases of modernity’, potentially triggered by the gradual incorporation of refined starches, sugars, oils, and heavily processed foods. The certainty of evidence linking unprocessed red meat and whole-fat dairy to the emergence of such diseases is low, challenging prevailing dietary paradigms and emphasizing the need for nuanced reconsideration of the role of grassland-derived foods in public health.