I still haven't really figured out how CR is supposed to be sustainable. I am around BMI of 19, and have been as low as 17 (6'2", 133lb). I become extremely unhealthy when I don't eat enough. As far as I know, I can't eat less and maintain the same weight. CR would, for me, send me to the hospital. Is CR just another name for "lose weight"? Is it working towards a goal rather than a lifelong steady state of living?