That food should be fresh and natural has become an article of faith. It comes as something of a shock to realize that this is a latter-day creed. For our ancestors, natural was something quite nasty. Natural often tasted bad. Fresh meat was rank and tough; fresh milk warm and unmistakably a bodily excretion; fresh fruits (dates and grapes being... See more

You have to consider what comes along with the protein – things like cholesterol, saturated fat, drug residues, pathogens (E.coli and Salmonella)