Eating one's own kind, is there anything more scabrous, almost inconceivable? Yet, in human history it has always been done, partly for ritual purposes, sometimes out of necessity, sometimes out of criminal perversion. But then, we ask ourselves almost jokingly, how nutritious is human flesh? Finally, there is positive cannibalism: that of the cells of our body, which feed on themselves, on their own waste, producing positive effects on our health.