The doctors issue a medical certificate based on the GCAA requirements for a healthy pilot. PASS or FAIL. Simple as that.
What people don't seem to understand is that the company then insists the doctor passes on specific information on your health to the chief pilots. IE: your BMI.
The CPs then decide on what action to take regarding your health, which "may include dismissal".
Unfair? Unethical? Illegal? Welcome to the Middle East. And the company doctors are complicit in this sham.