GSD's can be funny to deal with sometimes - mine is driving me nuts right now. She gets really bad seperation anxiety, so I have to ignore her unless I am telling her to do something. NO loving, petting, etc - and it kills me! But she destroys my house, otherwise.
As for the eating thing, I haven't had that problem with my gsd, but I did with my Border Collie. What I started to do: I would put down the food bowls, and when I felt like it, release the dogs to go eat. If my BC did not eat, or did not finish her food, then the food was picked up until the next mealtime. She now eats nearly every meal just fine.
The BC was used to having free access to food, but after getting a rescue dog, we couldn't leave the food out because he would have eaten till he was sick, and then probably some more. We had to train the BC that mealtime was mealtime no matter what.
It's not always easy, but it does work
