There can be many mechanisms for this effect: One possibility is that your friends say to you something like -- you know, they adopt a behavior that spreads to you -- like, they say, "Let's go have muffins and beer," which is a terrible combination.  But you adopt that combination, and then you start gaining weight like them.
造成这一现象的机理可以有很多。 一种可能是你的朋友对你说── 他们的行为传染了你， 比如他们会说：“咱俩一起去吃点糕点，喝瓶啤酒吧。”， 致命的搭配 但你还是接受了这个搭配， 你也开始和你朋友一般开始增肥。