GC, I can tell you that the two Chinese airlines I interviewed with did measure BMI. I was well within anyone's guideline so I can't say much about limits (ask me about age, sometime, though ). The Indian medical folks also measured it, but it wouldn't of itself be a showstopper there.

Showing up visibly overweight for a Chinese medical would put you at a pretty severe disadvantage, IMO. I don't know what they'd do with the classic problem of an extremely fit, well-muscled fellow who exceeds BMI guidelines but is in fact in outstanding shape.