Is it me or there are too many health-care professionals that are fat and obese? 
I went to donate blood yesterday and all the people working there were big. 
My dad had a stroke not too long ago. All the nurses I saw there were pretty big. Some were obese. 
My husband had a minor surgery last year. The nurses in the recovery unit were big to huge. 
These are health-care professionals. Shouldn't they lead by example? We expect our IT guys to be on top of IT (not that they always are). We expect our lawyers to be on top of laws and legal procedures. 
Why is it that we don't expect our healthcare professionals to do their best to be healthy?
		
		
	 
Your logic is terribly flawed.  You have created a straw man argument by both assigning a role to health care professionals and an attitude to the general public.  Neither is your prerogative. 
The public doesn't look to doctors and nurses to be idealized athletes and bodybuilders and paragons of fitness.  We expect them to give care for the sick, which they do.  We expect them to know hygienic practices to preserve the sanitation and sterility of medical facilities and equipment, which they do.  We expect them to be informed and current on diagnostic means to detect and diagnose maladies from observing symptoms, which they do.  We expect them to listen to our descriptions of our conditions and accurately record them and maintain records for future benefit, which they do.
Ask any child in school who they look up to as fit adults, and nary a one will say their doctors.  To a man, each will say an athlete or a model or a star.  Doctors are service providers, not role models.
If they were role models, we'd all be clamoring to fuck people over with excessive charges for our services so that we can have 2nd homes, so that our children can attend first tier schools and colleges, so that our vacations can be expensive and frequent, so that our first wives can have their alimony and we still have money left over to pay for our younger 2nd spouse, and so that our vehicles can be more expensive and superior to those of our patients.
And, let's take your premise, that laborers and professionals must be paragons of the ideals of their chosen careers. 
College athletic staff should all be pursuing higher education because they are affiliated with universities.  They should be more learned than the general public.
Farmers should be consuming the crops they grow, otherwise we should question their commitment to their livelihood.
Lawyers should encourage their clients to confess their crimes, as law is supposed to uphold justice, and it isn't just for a guilty man to get off without paying the penalty for the crime.
A meatcutter at the local market should be eating the animals they are cutting up, else they are insincere.  Their arteries or health shouldn't be a reason not to eat red meat all the time.
Waiters should be eating out and giving generous tips regardless of their expendable income, as they should set an example if they want us to give them tips.
Bartenders should be regular drinkers in their off hours.  How else can we trust that they are living the values they espouse as bartenders.