How might global health evidence waste away? The thing that generates evidence in this case, the metabolism, offers some possible answers to this question. But it does so, sometimes, only when things devolve. This essay takes up the case of amputation in the case of diabetes. The ethnography of atrophy highlights how knowing and embodiment wither, all while the thing that is supposed to absorb the world – the metabolism – offers less and less return on such a promise.