Howmany times do you force feed per week and howmuch per day? An adult should eat once or twice a week, or several small meals on it's own. If you have to force feed that long, something must be wrong.
I really hope your not force feeding on a weekly basis, because if you are the frog has no chance to be really hungry.
I do think it might be a good idea to drop the forcefeeding for a week or two or even three, to check his response.