I really enjoyed reading all of your comments regarding GoGo and I'd like to share some of my input regarding GoGo.
I do agree that something need to be done about his weight.
I had a cat who I adopted about 1 1/2 years ago and she was FAT and BIG when I adopted her or was it her adopting me?? Her name was SunniDay but I called her Sunni for short and she was about 9 1/2 years old.
Anyway, the vet weighted her in at about 15 pounds and told me that Sunni couldn't gain any more weight. He started lecturing to me about this and I was like, "Hey! I just adopted her so I am not the one who let her get fat!"
As I lived with her and watched her throughout the years, I noted she'd push Zebra (another cat) out of the way and eat Zebra's food so I had to make sure that didn't happen very often. One way I tried which worked was to cut out a small door out of a cardboard box and put it over Zebra's food dish and weight the box down with something heavy. That way, only Zebra's head could fit through the "door" in the cardboard box and prevented Sunni from eating Zebra's food. That helped her not to gain any more weight...
After 1 1/2 years of SunniDay living a very happy life with me and Zebra, I had to put SunniDay to sleep on April 23, 2002. She had kidney failure and lost over 5-10 pounds within 2 weeks. I tried everything to lengten her lifespan and lessen suffering but after 2 weeks, I knew she wanted to go so I had to let her go.
I have heard that weight can be a contributing factor in kidney failure. Just thought this might help.