I need help with training "Drop it" command

I have Labrador and he is such a foodie. I want to teach him "drop it", but everytime he smells or senses treat nearby, he just never holds, catches or fetches anything except to eat the treat. Even though if I am being sneaky for first time that I didn’t let him know that treat is nearby, then the second time is same above case. He just want treats, that’s all. Help!