eat one's word并不是真的把文字吃下去，不是“食言”！而是指“收回前言，承认自己说错了话”。

【例句】
What he said proved wrong, so he had to eat his words.
事实证明他说错了，所以他只好收回前言。

I think you will have to eat your words some day.
我想总有一天你会承认错误，收回你之前所说的话的。