I'm thinking of stealing food to feed a hungry cat.
Why would you steal food to feed a cat?
I don't have any cat food on me.
It's nice that you want to take care of an animal that's in need but you shouldn't be stealing to do so. Even if you think you're doing a good thing, stealing will always be wrong.
The place I get it from will not need it as much as this cat.
Just take the cat to a veterinarian if you want to help it out. Stealing is not the answer, even if it is with good intentions. Wanting to help the cat is admirable.