re: Is diabetes in cats a death sentence if untreated for a little while?

I have a cat that was near 18lbs doing the same stuff...vet considered him obese and diabetic....I wasn't about to pay for bloodwork for something my wife found in a parking lot. We put him on a crash diet for several months, lost about 8lbs. He still pees more than what I think he should but its not on our stuff like it was. Granted he is 13 years old but is considerably better. Just my 2 cents.