I have a question with regards to having food at a non-muslim’s place.
Many of us face or have faced situations where our friends, colleagues, acquaintances etc had invited us over at their place for lunch/dinner.
So we know that Islam is very particular about halal/haraam food, and in certain cases we may not know whether the food that we are having or are about to have is haraam or halal, or if it has been prepared by a hygienic person or not.
My question is that can we eat at a non-muslim’s place if there comes a point where if we don’t eat, the host may feel bad about us rejecting to have food with them because of them being non-muslims?.

God has created man in a way that whatever he eats and drinks has an influence on his mind, body and soul. 
Haram food effects the soul in way that he won't be able to do any good actions.
As far as eating in gatherings from a non Muslim is concerned, one should be careful to avoid it and try their best to excuse themselves. Although however, if one were to ask Can we eat food cooked by a non Muslim when we do not know whether or not it is clean? According to Ayatullah Seestani, the answer is that a Muslim is allowed to eat any food made by a person whose faith and religion is not known to him, no matter whether that person touched it with wetness or did not touch it, provided that he does not know or is not sure that the food consists of what is forbidden to him.
Also It is permissible to eat the food and it is not necessary for the Muslim to question the person who prepared the food about his beliefs or disbeliefs, or whether or not he had touched the food, even if that inquiry is very convenient and natural for one who wants to ask.
If he knows for sure that they are disbelievers, then it becomes haram for one to consume the food however difficult it may for them to convey to their hosts and in such cases, one has tp either tell them with politeness or find an excuse not to attend the gatherings.