One recommendation that I have heard and think is great is to put the bowl down empty and wait for him to look to you. When he does give your good job cue and throw a piece or 2 in. Wait for him to look to you again for the food. Keep throwing in just a bit slowly getting closer to the bowl. You want to work your hands closer and make him look to you to keep replenishing his bowl. Eventually you will spend his whole meal with your hands right next to his bowl as you slowly add the food once he looks to you. If he ever growls, freezes, hunches over the bow, etc. you say no and walk away (and the food bowl stays empty for awhile), then try again going a little slower. Eventually you work up to 1/4 of his meal before you add more with your hands there the whole time. Build up to a whole bowl at which point you move away once he is given it. Then you start to approach and drop something even better than his food in the bowl (chicken, steak, hotdog, cheese, whatever). Throw it in and then walk away. Keep doing this until your approached gets him excited for his special treat. Once he is excited by your approach for a bit then wean off the treats to only every so often when you approach. So approach most times and give nothing but praise but every so often give him that jackpot. By the end he will understand all food comes from you and when your hands come near his bowl you are going to give something better. Do not take his bowl away just to prove you can. He is afraid of you taking what he holds valuable and taking away the bowl will just reinforce that fear. You want positive associations not negative ones.