you female my be gravid ( full of eggs), and females seem to eat more then males, since they are larger.
my male dwarfs were always very skinny (although not unhealthy) when compared to their plump, pear shaped females.
your male sounds to me like something internal is going on. a parasite or bacterial infection. not sure though...
i had a female who would always roll around on her back and side. she would even eat upside down! not sure what her problem was, but she lived for over 5 years just fine.
