*sighs* Alas, we're stuck with canon depictions, which make it very very clear that a) bodyfat ratios are probably not a problem and b) Kishimoto has a boob fixation. This despite the real-world effect of the kind of physical training that would allow a person to bound through trees at highway speeds. *sighs* Hello canon contradictions.

There actually /does/ seem to be a lot more in common between Naruto ninjas and a standing army than between them and anything remotely like historical ninja, including the limited ratio of shooters to logistical tail. It would make a nice rationalization of the above, except that the most peak-condition women tend to be the ones with the most pneumatic chests, and so far the two actual on-screen pregnancies have been 'shooter' grade women actively in the field at the time.