Is it discrimination?

I have recently read/heard on the news and in conversations with friends and colleagues that employers don't want to hire people who smoke and/or are overweight because the health insurance coverage for these individuals is higher. Well, that seems logical. Isn't it in an employer's best interest to be fiscally responsible? Is it really unfair for employers to want to protect their bottom line? If I'm running a business, isn't the whole point for it to be profitable? Employees are hired based on what they can bring to the table; if they are costing the company more than they can produce then it makes sense to me that it would limit their employability.

Is it really discrimination? Could one argue that if an employer can only afford so much for healthcare coverage and the coverage is, therefore, limited because of the predisposition of a few employees, i.e. smokers and overweight people, that it is unfair to healthy, non-smoking employees because more coverage would be available to them if not for their "at risk" colleagues? I don't know if that's the case . . . I just wonder about these things.

Here are a few articles I found interesting . . .

Overweight Workers Receive Smaller Wages, Possibly To Counter Health Costs, Study Finds

COMPANY FINES WORKERS FOR BEING OVERWEIGHT

Employers get tough on health: Some take punitive steps against smokers, overweight workers

The Business Shrink