The doctor warned that if he didn't change his diet, he would become obese.

obese 是形容词，意思是"过度肥胖的"，指体重严重超过健康标准的状态。这个词来自拉丁语obesus，由ob（表示"过度"）和edere（表示"吃"）组成，字面意思是"吃得过多"。