很多人都会说，自己年轻的时候，怎么吃都不会胖，年龄大了，稍微多吃一点就会变胖。对比自己以前的照片，经常会发出感慨：岁月是一把杀猪刀。为什么年纪越大，人就越容易长胖呢？

Modern life makes us tired, right? But research from societies in Africa and South America suggests people in the ancient ...