There is pretty strong evidence from skeletal archaeology that early farmers were less well-fed than hunter-gatherers, suggesting that although agriculture supported population expansion by allowing a larger total number of people to be fed, it didn't always produce more food per person.
That doesn't sound so surprising, it's more the... er...
extensions from that mentioned here that are a little on the strange side (as you say, of course) and which prompted the remark.
Although, just to randomly make things stranger perhaps, there are farmers and there are farmers. Major differences between pastoralists and people that grow crops and so on.