My Sim was pretty thin coming out of CAS, but it seemed she gained weight rather rapidly. I bought her a treadmill and she uses it daily. Now it seems like my Sim has become extremely muscular, but ...
It seems to be a problem a lot are coming across,Sims gain weight way too easily and become a muscular block when you try and make them lose it. Apparently the 'bug' has been noted and Gurus are looking into it.