There's also something that scientists have talked about called the thrifty metabolism.

科学家们也谈到,所谓的节俭代谢

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

Now thrifty metabolism means you make very good use of your calories.

现在,节俭代谢是指你充分利用卡路里

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选