>>1101490My basis on a low bodyfat (15% and under) being less healthy is based on the fatigue caused by it. Even people that work out a lot don't "naturally" get down that low, they need to purposely diet and not eat when they're hungry. All body builders feel like shit when they're competing and there are examples of them collapsing on stage.
I was down probably close to 12% not that long ago and I always felt like shit and feeling like I was going to feint, I even did twice, now I'm at like 16-18% and feel a lot better.