Chinchilla eating little to much

[Aweminccino]

My chinchilla,which I got a month ago is overweight.It's not get that much exercise as I want it to get,but just wants to eat or sleep.And it is eating a little
more than it should.Any help?

 

[Cuddlebug]

Why do you say he is overweight? What do you feed him, including snacks?