Well, it could stimulate hunger so people just want to eat more.

它可以引起饥饿使得人们食欲增加
It could stimulate satiety or suppress satiety,

可以刺激或抑制饱腹感中枢
either one depending on whether you eat more or less.

导致你食欲增加或减退
It could affect the sensory--how you perceive food,

还可以影响到感知你如何感受食物
so if you get a certain amount of pleasure from food x,

如果你从某种食物中获得一定的愉悦感
pizza let's say, or a donut, or ice cream

比如匹萨甜甜圈或冰淇淋
or whatever it happens to be

又或是任何一种在
under non-stress conditions,

无压力情况下吃到的食物
the one hypothesis is that if you're stressed, your physiology changes

某假说认为在压力下生理上会有变化
so you derive more pleasure from those foods.

因此你需要更多这样的食物来令你开心
It could be that the foods have a whole different biological effect

也可能食物会引起与我先前所提
than what I just mentioned,

完全不同的生物学效应