Thanks for the positive replies.
Honestly, he does not eat very much! I would say on average he was eating 100 grams of protein per day, and maybe just over 3000 calories. He explained that during his competitive days he closely watched his food and protein intake, but after stuffing so much protein in for 18 years he's sort of sick of it and now just eats what he wants. For example, a typical breakfast would include cereal, oatmeal, bagel with nutella, some fruit, and milk with the cereal - the only protein in the meal coming from the milk. Post work-out once he only had strawberry crepes which had no protein at all. Usually about twice a day he will have a fair serving of meat, but does not have any protein shakes otherwise.
How is he able to maintain 300+ lbs on such low protein intake? Genetics.
And yes I got to meet Sato! She is also huge (135 lbs), and very friendly. She did not bark at me the whole time I was there, and we got along very well - once she even fell asleep next to me. He takes her for walks twice a day, and sometimes to the beach as well. Sato's diet does consist of some dog food but mainly mesquite turkey, roast beef, steak, rice, etc. One evening the Three Times (at least) Uncrowned Mr. Olympia cut her up a very large steak and she ate it in about 10 seconds!
More pics - some with Sato in them and the fourth at the Wild Animal Park