From the Editors of The Daily Cat
Losing some weight will greatly improve her situation. After consulting with your veterinarian to rule out any possible health problems, try to get her to exercise more. Play with her several times a day with her toys (also consider getting some new ones to spark interest). If she's not used to playing, you may have to start gradually, but you should be able to get her moving around more than she probably is now. Consider feeding her food that is specially formulated for less active cats. Also, brush your cat daily, which can help your feline with the clean-up chore.