If you take in more calories than you consume, it gets stored in the fat cells, that's the energy bank that you can draw upon if you don't have enough food and starvation or famine were an issue.

如果你摄入的热量超过消耗的,热量就会存储在脂肪细胞中,这就是能量库,你可以在,食物不够以及饥饿或饥荒的时候利用它

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选