to bite off more than you can chew

Origin

Imagine a child, eyes bigger than their stomach, grabbing a piece of pie far too large for their little mouth. They struggle, cheeks bulging, unable to properly chew or swallow. This vividly literal image, a common and relatable experience, is the heart of the phrase. It’s a simple, powerful metaphor from the everyday act of eating, first appearing in print in the 19th century, that perfectly captures the universal struggle of attempting a task or commitment that far exceeds one's capacity, leading to discomfort and difficulty.