Those are the rules, Hon. You see many cadets or young officers with big bellies?

You have to be able to meet certain physical criteria. For example, I wasn't accepted into the Marine ROTC, which was my preference, since I didn't vision they deemed good enough to see without corrective lens.

I don't think that there was a "weight" clause per se, but even if there was at most I weighed 180-185. But, you took physicals. And, to keep the scholarship, you had tasks to complete, like running a mile in a certain time, for instance.
IIRC, my instructors at Lehigh, who were officers, had their own to complete as well.

At the time of the injury I spoke of, I was a 34" waist, but likely should have been a 33" or 32". After that for years I was a 36".

I only really started pounding on the weight after I had the cartilage removed from my right knee in July 1984. By 1988 I was a 40". By 1994 a 44". By 1999 a 50". By 2003 a 54".

Honestly, I've known MANY fat guys with bad knees. But, I don't know many fat guys who blew out their knees while fat. Fat guys don't usually extend themselves in sports to tear knees, which is when, in my experience, most knee injuries occur.

Sitting at a computer and getting pizza delivered isn't conducive to knee injuries.