I searched the site extensively before posting. I've been slim my entire life 35 years old, 5'5'' never been above BMI of 20, (currently at BMI 19). I don't have an eating disorder and I practice loose "CR"- I eat large amounts of extremely nutrient dense fibrous foods and am careful about getting all nutrients from whole foods with very few supplements (calcium, the Bs etc); I know I'm thin, am not driving to be thinner etc. Recently, and probably because of a slight amount increased energy expenditure (my walk to work changed and is longer) my period stopped.
Googling around and this appears to be called "functional hypothalamic amenorrhea" and comes from a "negative energy balance" (aka CR). All the "treatments" I've found online are to eat more calories and especially more "junk foods." Some women report gaining 15-20 lbs to regain fertility. Has anyone researched this? The main bad effect appears to be bone loss, which I know some of the men on this site have complained about.
Having too little estrogen is connected to premature aging, not the other way around, so that's not what I want! Also, I'm using "fertility" as a shorthand, I'm not trying to conceive, but simply be as healthy as possible and not lose my bones!