The problem if you have been free will feeding them for 3 weeks is the damage is done, most likely. You will lose some even if you change their eating habits now. I am not saying you should not cut way, way back, Just know the roots of kidney and heart problems have most likely started already.
I know this will sound cruel to some of you, but I actually skip a day or two a week with my "toads", I want them on a near starvation diet to increase their life spans.
BTW they are huge birds, I am hoping I have not over fed them this year.