Getting healthy is a great thing. And as someone who has done it (with varying degrees of success) in the past, I can confirm that those first few months of making a change are really, really hard. You want to talk to people about it, and let everyone know the progress you've made.
But you shouldn't be an asshole. And yet, so many people are when they get on the health train, and it's usually because they are doing one (or all) of these 6 things.
1. They get really pretentious about "eating right," when they should be the last person to judge.
It's one thing to encourage people to eat more fruits, veggies, whole grains, and lean proteins along with you. You can post photos of what you're making, talk about how much you enjoy salads or whatever, and generally keep things positive. But going on condescending rants about how sugar is the devil, and the occasional fast food dinner is basically child abuse, is pretty rich coming from the person who two weeks ago was eating Arby's four nights a week. It's all about moderation, and immediately going from "super unhealthy" to "judging the crap out of everyone for not being as reformed as you" is pretty uncool.
2. They post before & after pictures... before there is a difference.
There is no reason to post a photo of yourself every two weeks to show #progress, particularly if there isn't actually any visible change yet. If you're making your lifestyle change specifically to see immediate visual results, it probably won't last, and chances are your Facebook page (instead of, say, the community at r/loseit or whatever) is not waiting on the edge of their seat for yet another photo of your nascent abs. It's nothing personal, it's just probably not the best thing to be doing for long-term, slow-burn healthy lifestyles.
3. They become way too into #fitspo.
They post tons of memes about "eating clean and training mean," or "destroying what destroys you," or "moving more." Which is fine, but no one needs to be sharing those dumb things five times a day, especially when like 40 percent of them seem vaguely dangerous/unhealthy. Like, we get it, you're losing weight/getting built and you are #motivated to #work #harder and #go #farther. You don't need to tell us through endless picture of people eating avocados in complicated yoga position.
4. They also post mirror selfies with 1,000-word captions about how #blessed they are to be making this change.
I don't know why this is such a phenomenon, but it seems like no one is capable of getting healthy in any way without writing The Odyssey under their profile picture, I guess to make sure that everyone knows how intense and powerful their journey has been so far. Also, considering these pictures/manifestos tend to get posted once every other month, I can't imagine they are THAT life-changing.
5. They go around social media giving unsolicited advice about food/exercise/general life.
It's fine if you have decided that you are only going to eat raw vegan food for the next six months or year or lifetime, whatever. But the moment you come onto my foodporn Instagram pics, or status update about how I just crushed an entire pizza while watching Netflix on my couch all afternoon, to come give me some undesired ~words of wisdom~ about how I could be treating my body better, we have a problem. No, I don't want the gross healthy version of mac n cheese where every good thing about it is substituted by some variation of a soybean. I want mac n cheese. Stay in your lane.
6. They suddenly become really body-shamey.
There is nothing sadder than someone who gets healthy/swole/thin and suddenly becomes incredibly judgmental to people on the other side of that line, but it's really common. For some reason, right after "peaceful sense of accomplishment," "need to go on a rant about how fat and lazy people are" is the next emotion that people experience when getting healthy. And whether or not their judgments are based in any kind of fact, the point is that they would not have appreciated it a few months ago, before they embarked on their journey. Being nasty about other people's bodies doesn't help anyone, or make positive change. Even if it feels good in the moment.