have eyes bigger than one's stomach字面意思眼睛比胃大和汉语俗语“眼大肚子小”的含义一样，用来形容“人眼馋，看到什么都想吃下肚，却因为饭量有限，没办法吃完”，即眼高手低，人心不足吞蛇象”的意思。

【例句】
My mum told me off because I had ordered three ice creams and finished only one. She said I had eyes bigger than my stomach!
我妈妈把我教训了一通，因为我点了三个冰激淋，只吃完了一个。她说我人心不足吞蛇象。

You think you could eat that entire cake? I think your eyes are bigger than your stomach.
你认为自己能吃完整个蛋糕吗?我看你是眼馋肚饱,根本吃不下。