Here is Rascal. I took this picture yesterday. He was sitting on my desk glaring balefully at the dog.
Rascal used to be overweight. He weighed 15 pounds on a frame that should carry more like 11 or 12 pounds.
And he ate dry cat food.
Then last summer I noticed he was losing weight, drinking a lot of water (and peeing a lot), and his fur was stiff. At first I didn't pay too much attention to the drinking and peeing, after all it was summer and it was HOT.
Then one day I discovered that he'd, um, found a non-litter box area to be his new bathroom. That's when I decided he needed to go to the vet.
He was down to 10 pounds. His glucose was in the 500's.
The vet put him on insulin and special low-carb food.
Diabetic cats can sometimes go into remission with treatment, and Rascal went into remission very quickly. He's been off the insulin for about 3 months now, still eats the low-carb food, and his glucose has consistently been around 80 for the past several months. His fur is soft, silky and pettable. His weight is around 11 pounds and has stayed pretty stable.
Proof that cats need to eat what they're evolutionarily meant to eat.
So that got me thinking. If cats get sick on food they're not evolved to eat, and if they do well on food they are evolved to eat, shouldn't humans be the same?