How do I stop her??

What are some ways to keep my dog off of my counters? She is a Great Dane and can reach any shelf in my home. Her room that I keep her treats, chewies,wet food, ect in. She gets her front paws on the counters and she will get a hold of it ant eat it all and make herself sick. I have no place else to put that stuff and she shouldn't be on the counters anyway. I'm about to kill her (not literally, just really mad at her). I feed her 4 cups twice daily, she gets treats regularly, she gets chewies once a day, she gets to go run and play for 4 hours and gets an hour walk. She is not bored and has many toy's. I don't know why she is doing it and she gets the exact amount if special food assigned by her vet.

* She is almost 2. I know, still very young, I just want to start training now. She only started this a week or 2 ago.

**

I can't afford obedience training. it needs to be something I can do myself.