I have no argument with any one who consumes a "healthy diet". I just don't find it logical that a "healthy diet" would result in cessation of menstruation. If a "healthy" female is properly nourished, does it not follow that she would have a regular menstrual cycle? Biologically speaking, the female's role is to birth the young. Don't get me wrong on this point, please. I'm talking biology, not life choices.
If a woman of childbearing age is not on her cycle, I would say that that points to some imbalance. It is not a natural state of affairs.
We're here to breed. It is a luxury that in these times we can choose not to, that we can choose a diet/lifestyle that does not support that.