Lose weight your job in danger!

When employers speak of medical exam and background check, I never thought that I had to worry about the former. What I worry myself with is my credit record as I have disgruntled some creditors(read bank credit cards). I never worried about the medical exam cause even though I am classified obese, I have always met blood pressure requirements, was never diabetic, although once a doctor did say I need to bring my (bad) cholesterol down. When I went for my last check I was told blood pressure slightly up but I figured I have not been exercising because I broke my leg but nothing to loose sleep over.
So imagine the surprise when I get a call and the advice is lower your blood pressure and reduce your weight. It did not sound like my prospects of securing employment were diminished but that could be me being optimistic. But imagine if my blood-pressure was a big problem!
It seems there is a consensus amongst employers that one must be in good health to carry on a 'certain' job. I guess that diminishes your chances of taking sick leave etc. BUT its a bit sad that a fat person has the stakes against her, cause almost all lifestyle illnesses are linked to weight. Do they ever check the liver really to see if they're not hiring an alcoholic.
This is two-sided for me, there is your 'health is at risk'(I can't employ you) and looking fat/obese(I don't want to employ you).
I know there are professions that weight is really important, recently in South Africa, there have been public complaints that police officers are fat (not unfit), they will never keep up with criminals. But I know lots of people who are classified fat but are so fit, they can chase anybody. Just like there are thin folks that could not run to save their lives.
I have recently read as well that an indian airline has dismissed overweight stewardesses- I guess it can be hard for big people to move along air plane aisles, could that be it? What puzzled me with the airline is the fact that they say the managers want to keep up with competitors by employing fit stewards. Does this mean they just don't look the norm?
When Penelope Trunk wrote about one needs to be attractive to move up the corporate ladder, I was like whatever. I mean I am bright, I love my job, so what if I am fat(leave the fact that I am trying to loose weight, that is besides the point). Is it really possible that people are biased towards fat people.
Just the search "fired for being fat" shows a fireman who was dismissed but reinstated (with conditions) after some protest and a football player who was warned to lose weight, he didn't and he was fired.
In trying to climb the corporate ladder are my chances that diminished because I do not look like I can climb the ladder?