Haopee, Do you dogs like their dog food? If the pieces are small, you can use those for dog training, too. Also, you can use baby carrots cut up into pieces. Other vegetables work good, too. If you have Cheerios, they can be broken up into many small pieces very easily.
At some point, you can work in praise in place of the treats so that you aren't using so many treats. There will be a point where you'll dog will be happy to get a scratch on the chin and a kind word. It takes time to get there, though.
I have a similar problem as you as my dog is small (10 lbs.) Though, she does not know the word "full" when it comes to food. If I kept feeding her, she would keep eating.