Caloric intake and exercise levels have not altered enough to explain the difference, the scientists maintained, and human genes cannot have changed in such a short time. 科学家们认为热量摄取量和运动的多寡也无法解释该变化，而人类基因在短时间内也不可能发生什么变化。
Keep a count of your calorie intake for one week. 把你一星期的热卡摄入量记录下来。
