My friend thinks that I'm going to pay for his food, but I'm not.
Really?  Are you sure that he is able to pay this time?
I'm the one who paid last time, he didn't offer to.
It's wrong to not help a friend out. You should pay if he's not able to. If not, you could damage your friendship.
Why does he need help with food? I am not paying for his food, I am going to take his food.
It sounds like your friend doesn't have the money for his food, and as his friend you should be willing to help him this time around. There should be a lot of give and take between friends, and if you're not willing to do that then it sounds like you might not want to keep him as a friend.