تعریف و معنای "{one's} eyes are bigger than {one's} (stomach|belly)"

What is the origin of the idiom "one's eyes are bigger than one's stomach" and when to use it?

The idiom "one's eyes are bigger than one's stomach" is used to convey that someone has taken more food than they can actually eat, often due to greed, temptation, or overestimating their appetite. The origin of this phrase is thought to be based on the idea that when people see a variety of appealing dishes, they may serve themselves more food than they can physically consume, leading to waste or discomfort.