Well, not being fat doesn't mean you are fit, but being fat is certainly incompatible with being fit. I speak as a fat guy who's probably less unfit than 95% of people at my weight (over 320 lbs): I'm still not "fit".
I guess it depends on how fitness is defined. I would say a person can definitely have good cardiovascular fitness while being fat. They could also have strong muscles, low blood pressure, low cholesterol, normal glucose levels and generally be healthy. I would describe that as being fit.
Seems like weight should be considered one indicator of fitness but not the most important one.
Heh. People used to spontaneously call me that when I was a kid (due to my name "Randall Randall" rather than my size, I expect), and it's way easier to google for. :)
Curious if you've read Catch-22. One of my favorite characters in the book was called "Major Major" (and of course his rank was Major). At some point they managed to get a 4th one on the end too.