Though its origin is disputed, the phrase "the proof of the pudding is in the eating" is popularly attributed to Cervantes 1615 comic novel Don Quixote. And while one can talk about a pudding's ingredients all they want, the saying's meaning stays intact when shortened to "the proof is in the pudding" - because that is where you will ultimately find it; if you bother to at least taste it - as it's the results that count.