Ok, let's be honest. We have ALL had those moments when we see someone and judge them prematurely. We all have our built in biases we've gained from years of experience interacting with other humans, even those of us who do our best to suppress them. Some of us, myself included, really hate ourselves in those moments. Sometimes it can be hard to look at someone who is "morbidly obese" and not judge how they must be living their lives. Once you get in a bad habit of classifying those around you it can be extremely difficult to break.
So how do we stop?
It's not as difficult as you may think. The first step to progress is to get to know many different kinds of people. That means befriending those of different races, genders, sexualities, religions, backgrounds, body types, political beliefs, etc from yourself. The truth of the matter is that fat girl eating a burger doesnt need your judgment. She may be the sweetest person you ever meet. The big black guy with his pants around his face might be a great shoulder to cry on. The strict catholic republican may have more in common with the liberal lesbian than you would ever know, unless you started talking to one another. We're all sharing the human experience. We all have so many things in common. We're all loving, eating, drinking, sleeping, and breathing on this same planet and we have to share it.
It's unbelievably detrimental to your social and moral being to judge people on outside appearances or any one facet of their character. The more diversified your social is the more educated and informed you will be. If your Facebook news feed is 100 people posting the same article it might be time to switch things up. Maybe go to a different bar, take your dog to a different dog park, try out another church, go to an ethnic restaurant you've never tried before. Trust me it'll be worth it.