Answered by Shaykh Faraz Rabbani
Hyderabadi hospitality dictates that you have to eat a lot of food, even if you aren’t really hungry and you don’t really want to eat. The host will ask you if you want some; you’ll say no, to which the host will respond by putting the food in your plate despite your pleas to the contrary. Then he will ask you if you want more, to which you respond, no thank you, and he insists on giving you more. To refuse is acceptable, but not a reason to not be given more food. “No” has no meaning, and is taken as a “yes, please give me more so I can be sick.”

Walaikum assalam wa rahmatullah,
Simply refuse, with a smile, and say you simply cannot have more.
Such customs are excessive and one is not called upon to adhere to them.
Wassalam,
Faraz Rabbani