No. As I said last time, it does not suggest such a thing. We don't know why he can't wear them, and there are infinite ways in which a small or medium humanoid might be unable to wear leotards, so extrapolating a single interpretation from the fact is wrong. Maybe he has the wrong shape of legs (e.g. faun, hoofed, etc.), and finds them too uncomfortable. Maybe his feet are too large. Maybe his legs are too thick. Maybe, maybe, maybe. Drawing such a broad conclusion: "MitD cannot be a small or medium humanoid because he can't wear leotards" is pushing the fact's deduction way past breaking point.
Edit:
The exact wording is "can't fit...probably because of all the stew I eat". Not sure why "can't" would discard claws, though - leotards meant for human use can't fit clawed feet.
Edit2: And to forestall the expected answer, no, I do not believe we can trust MitD's given explanation that stew is to blame. It might be, but MitD tends to be wrong about this kind of thing (e.g. "The elf ate beans too" deduction in the Tower scene). I will grant you it is a plausible reason (I'm far from fat, but I doubt I could get a circus leotard on - those guys tend to have a very specific body type), but it is not the only possible one. I lean more towards "MitD stole a set of leotards, and tore them apart when trying to put them on, because he can't control his strength" explanation.
Grey Wolf