I did that when Winston was younger too. It only took a couple months for him to catch on as well
I think treats are a good supplement to their diet so something other than food may be a good idea anyway. I do a couple things for Winston...there is a large variety of dehyrated proteins on the market that come in treat form. Right now Winston has turkey but he loves chicken and beef just the same. Another thing he absolutely loves is frozen blueberries. They are his all time favorite and knows when I head towards the freezer he has done something really great! When I first gave him the blueberries, I had to make sure it was thawed enough for him to bite into so he could taste the actual blueberry - now he takes them frozen solid because he knows when he bites into it he will get the yummy taste in his mouth.
My vet did recommend to give him no more than 5-6 per day b/c if he only eats blueberries it might effect his bloodsugar.