Weird situation need help?

I recently posted a new question but I forgot all about this one. I live on my in laws property because of lock of financial stability. I am 21 and my fiance is 23.my father in law is always calling me fat and also calls my fiance fat( he's overweight himself with cholesterol problems). Ok so they do help us oit financially we only pay 400 a month which is great that they are helping us but evertime we buy takeout food and bring it home they are both telling us how we are gonna get fatter and we are wasting money. We get takout food like once a week because 1 its super hot and gets worse when I cook and 2 I need a break from cooking everyday. My fiance is so scared of his parents he hides the food in a bag and sneaks it into the house and it pisses me off. Is this ok? Do his parents have a say so over this because I don't think they do( we live in different houses). And what do I do to stop their comments?