Many Christians, and even post-Christians, give up chocolate for Lent. This self-denying act now sometimes seems to be simply part of a calendar of occasions for virtuous abstention: as with ‘dry January’, we do it because it is good for us. But the original theory behind the Lenten fast is that it helps those who undertake it identify with Jesus. After all, Lent originally commemorates the 40 days Christ spent in the wilderness before his triumphal entry into Jerusalem.