The hunter-gatherer foods that people on the paleo diet reclaim as 'good' foods largely consists of fruits, vegetables, fish, meat, eggs. fungi and nuts - things that, hypothetically, pre-agricultural communities lived on. This means the exclusion of grains, potatoes, legumes, sugar and dairy, or anything else that has to be farmed.
As anyone who has ever lived in Halls will know, a decent proportion of students and young people consume ready meals and frozen meat on a regular basis. It may not bother many to think that the beef burger they ate may have contained other meats aside from beef, but what else could - or already has - happened?