Does prednisone itself cause weight gain or the increase in appitite only if you over eat ?

Fluid: Prednisone causes fluid retention and some redistibution of fat tissue. I believe the weight gain is due to fluid retention and the increase in appetite which is a side effect of prednisone. If you watch your calories you shouldn't gain new fat tissue.

Both: Prednisone does cause an increase in appetite but it also alters metabolism resulting in a decrease in muscle and bone mass and increase in body fat.