This makes perfect sense to me.
That's why it's so important to not be all-accepting, and so important to be judgmental and in doing so to set a standard for yourself, and others that you choose to allow close to you.
When you don't the bar lowers for everyone. E.g. the obesity pandemic, as above.
It sounds a bit exclusive, and, I suppose it is, but there is a very simple reality here: rocket scientists hang out with rocket scientists and build rockets. Fat folks hang out and eat. Beautiful people hang and with beautiful people and workout. Pot heads hang out with pot heads, and get high. Seems pretty common sense, honestly, when you think about it to any degree. There's a certain degree of osmosis that occurs, like, it or not.
What amazing to me is when I get dick pics from fat folks, thinking I might desire them sexually for some reason. That's just silly. Sending dick pics is silly. Another whole topic, I suppose.
Firefighter kind of hits a point of lead, follow, or get out of the way. E.g. if I have a friend who gives up working out, let's say, and starting hanging with fat folks, for whatever reason, then, I'd coach him on how to begin recovery, and, if didn't respond, it would be time to cut him loose. Cutting him loose may not be the answer if we were close friends, but, I certainly wouldn't get involved with the fat folks. I.e., I'd probably coach him on recovery, and so on, but, the savior complex only goes so far. Our personal relationship would likely fade to some degrees (interests change) but probably wouldn't completely end. If it was just an acquaintance, I'd cut them loose.
With regard to the concept of obesity clusters, think about the typical office group of girls, or guys. We've all seen them. That group that sits up a table of food at Halloween and keep it there until New Year's. Certainly the study validates that "cluster" of folks congregating around that food, and also their rationalization of their collective bad behavior in regard to it: if Sally is going to eat fudge, then, I'm going to eat fudge, too. To me, that all seem very simple, very logical, and part of the human condition. Of course, there ARE obesity clusters, and bad behavior IS contagious. That's also part of the human condition.
There's big money in keeping folks unhealthy. I'd lay odds this study gets put on the back burner, but, in reality, it's just common sense 101.
To quote that oldest of old sayest, "When in Rome do as The Romans do." Folks rationalize behavior and certainly being around food constantly and fat folks and that whole unhealthy lifestyle is not a very good thing.
Spock also says this:
In an insane society, a sane man must appear as insane, in order to be regarded as sane. Call it peer pressure if you wish.
At the end of the day, it's honestly probably best not to associate with those people because of the various obvious reasons pointed out by the study and just plain common sense 101.
while i'm far from being an angel, i have gotten some of my suggestions to be taken seriously and some of them have lost a lot of their fatness. 
I eat well and workout 5 days a week, inspite of their habits. I'm not normal. Where is the help for folks like me that find having a wide variety of friends,yet maintaining my individuality, to be a good thing? 
