Do you free feed? Or have set food times? How many times a day are you feeding? Does he have fur siblings that make him think he'll need to fight for his food?
You need to show him that good things happen when you mess with his food. Try putting a couple tiny bits of cooked chicken or beef, or some cheese, whatever you'd like, in his food while he's eating - he'll probably growl, but if you take the food away, he'll learn that he has reason to be nervous that you'll take his food and he may get more resource aggressive. I'd keep doing this at each and every feeding, and he'll soon learn that yummy things appear in his food when you touch it.
Same thing with toys - if you take a toy from him, have him sit for a second and then give the toy back. He'll learn that its not a bad thing to have something taken away - and it will help when you need to take something from him that you don't want him to have.
He's just a baby, so it will take some time for him to learn to trust you.
