Originally Posted by macg
were recently breeding like rabbits
That's certainly a factor. Chasing and egg laying takes energy. My breeding imis aren't food restricted, and they stay pretty slim-ish. I do have a female by herself in a holding tank, and she's getting pudgy.
Like people, I would assume that there is a range of eating habits vs weight gain in frogs. I've noticed this in other herps -- some need to be limited as to how much I offer them to eat, and some stay slim on a very generous diet.