My cat is sad and nervous on a diet. How do I help her get through it?

Miss Mina, my honey, has been food obsessed since birth. *genetics* I had an open bowl situation from kittenhood but she really started to gain weight. I thought it was ok to be a chubby kitty but she started to be self-concious about jumping up high and couldn't wash her butt. Now she is on a high protien diet; twice a day and a small snack at night. But I can tell she is stressed out! She begs for food all the time. Is there anything I can do to distract her? I brush her and play a bit but she thinks about food all the time.