what is the origin of the expression the proof is in the pudding
- Origin: The original expression was âthe proof of the pudding is in the eatingâ where the word âproofâ really means âtestâ (like in geometry class). Different sources suggest different dates for when this phrase came into existence: 1  14th century according to the Oxford Dictionary of Quotations. 2  1605 printed example â William Camdenâs Remaines of a Greater Worke Concerning Britaine: âAll the proof of a pudding is in the eatingâ.