Should weight be a determining factor for being a protected class in anti-discrimination laws?

Let’s not get into a debate about the many issues surround weight in the world and how people should be healthier, etc. I am really interested in your thoughts about protecting this class of people from discrimination (whether it be overweight or underweight). It happens more than most would like to admit, so I wonder if it should be added. Remember, there are people who are either over or under weight because of medical reasons/conditions and not because they are just “fat” or “anorexic looking.” If the color of my skin is protected, why shouldn’t the size of it be as well?