In the Three Kingdoms Period (sān guó 三國時代,220-280AD), the king of the state of Wei (wèi guó 魏國), Cao Rui (cáo ruì 曹睿), wanted to select a very capable man to work for him. He said to his ministers: "When choosing a talented person, always beware of one with a false reputation. A false reputation is just like a picture of a cake; it can' t relieve hunger."

Later, this idiom came to be used to mean comforting oneself with unrealistic thoughts, without solving practical problems.

三國時代魏國的皇帝曹睿，準備選拔一個有才能的人到朝廷來做官。曹睿對他的大臣說：“選擇人才，不能光找有虛名的人。虛名好像是在地上畫的一塊餅，只能看，不能解決肚子饑餓的問題??！” 后來人們就用“畫餅充饑”這個成語比喻用空想安慰自己，不能解決實際問題。

畫餅充饑(huà bǐng chōng jī )
【翻譯】Allaying Hunger with Pictures of Cakes.
【釋義】畫個餅來解除饑餓。比喻用空想來安慰自己。
【例句】小王正在實行減肥計劃，每當看到別人吃好東西的時候，她自己畫餅充饑了。
【近義詞】望梅止渴、無濟于事
【反義詞】名副其實