Don and Outlaw - sorry to burst your bubble, but you do not get grounded for any particular BMI figure.
It is however, correct that the majority of sick days are taken by pilots with BMI exceeding 30.
So of course the company will want to address the issue to become more efficient - and as a consequence, those pilots who are overweight will lose weight, become healthier, happier, etc....
It also seems to me that the only pilots who have a problem with the policy, are the ones who are overweight!