Which is to say, if all of my body fat were to suddenly, spontaneously melt away - beside that being rather unsettling yet decidedly convenient - I'd have 126.65 lb. of muscle and sundry accounting for me.
A healthy body fat bare minimum for women is quoted at around 10-12%. So, even at my extreme leanest while still remaining healthy, I'd weigh roughly 140 lb.
140 lb?! That's essentially what I weighed in high school. I was an athlete in high school, but I never trained at the intensity levels and frequency that I now train in Crossfit.
So, if I continue to eat a paleo-oriented diet, and to train responsibly, I may very well add some more lean muscle mass, even as I continue to lose body fat. My lean muscle mass may increase to the point that a theoretically "healthy" extremely lean 12% body fat me could still weigh over 150 lb. - and I am 5'6"...5'7" on a fluffy hair day.
I could ultimately end up my leanest, strongest, healthiest self without ever coming close to the low prescribed total body weights that I've seen for my height on various tables and formulae. If I'd have to sacrifice what hard-earned strength and muscle mass I already possess to fit some preordained one-size-fits-all metric for a 5'6" woman's body weight, then you can count me out of ever hitting that milestone.