I'm going to give a homeless man the half-eaten leftovers of my meal
You can't buy them a whole meal?
It is the best half-eaten meal I've ever had and I'm going to do something nice for once.
Your intentions are nice since you're helping the needy, but it is disgusting and degrading to give someone half-eaten food. It makes it seem like you think they are not worth a fresh, sanitary meal. It would be better to buy them a full untouched meal.
What, we are only talking about some food. If you only knew
I know that half-eaten food can be unsanitary or unpleasant, but someone desperate might eat it anyway. It isn't kind to give someone something that they will only use because they have to. A restaurant wouldn't serve half-eaten food, so maybe you shouldn't serve it to a needy person.