I never even realised this was a problem. My kid did sloppy poos for ages and ages. It didn't affect his weight gain or height growth at all. Admittedly when I stopped giving him oats in the morning and eased up on the yoghurt it improved, but it probably didn't change until the last few months, probably a bit over 18 months (I never really took note as to when it changed, I just figured it was part of the growing process). Most likely it changed when I started giving him really chunky food to eat.