Assuming you're male, 140 is the lower bound, so, you know, much lower than that might be considered anorexic, but in the 140s is not necessarily unhealthy per se. That's why it's the lower bound.

I am your height and when I was in my 20s, I think I was in the 140s, later I was a little over 200, and now I am just about 185. So the range makes sense to me, but I've never been far from completely sedentary. I know a pro sports player at ~200 would be very skinny. I think Mariano Rivera was an example.