As a biologist, my intuition is that there's been little change in the nutrient value of meat. Plants synthesise a very broad array of compounds which affect th

As a biologist, my intuition is that there's been little change in the nutrient value of meat. Plants synthesise a very broad array of compounds which affect their flavour and nutrient value. Animal biochemistry is nowhere near as complicated, so there's not so much that can change. There may well have been a shift in the protein/fat ratio of meat, but I guess that would be dwarfed by changes in what we eat and how we prepare it.