How it goes from here depends to a large extent on you. If you fight it you will make this much harder than it needs to be. The process becomes much more about what you are not getting and, sadly, as a focus that is always much stronger than what you are getting. It becomes a battle rather than a journey. It does not make it easy (no apology offered) but it does make it easier.
Breaking away from the pack makes you vulnerable - to assault from the other members of your pack as much as anything else. If you start to deviate from the accepted "wisdom" you can expect people to haul you back in. We can see how this is a useful survival instinct, a way of guarding the continuation of the herd, but it has its downsides.
The office is, for many of us at least, the modern savannah. Look around you, you spend more time with these people than you do with your blood family. And you have "chosen" to associate with these people [and that is why it is easy to get disheartened, or overjoyed at work. You are looking for/expecting to find similar values and attitudes - and indeed, we can start to adopt the prevailing one. BUT finding it contrary to your values is a betrayal, an isolation. AND at some level there may start to develop a concern that you are actually looking into a mirror and seeing a reflection of yourself].
So, imagine that somebody next to you starts to eschew the biscuits and cakes. They are not normally known for dodging the snacky cakes and hogging into the salad/veg. Having checked for a goatee to rule out an evil parallel dimension incursion, you ask the question - "Dude, WTF. Cake!" (or words to that effect!).
You will probably hear something to the effect of - my clothes had got snug, so I needed to drop some weight or, I saw a photo of myself or caught a glimpse of myself in a mirror/shop window/lake and realised that the bloater staring out was me, or I have health reasons for wanting/needing to drop some pounds/chub.
You smile indulgently, full of support (although a little confused as you've just witnessed a cracking in the pigeon-hole that person occupies in your mind). However, we have all heard this sort of thing before, so part of your smile stems from the knowledge that it will pass! After a couple of days you wonder when (if?) they'll crack.But it's ok, you start to see early signs of temptation etched on their face.
Partly out of concern - few people like to see suffering (and they must be, deprivation is unnecessary) - and partly out of a desire to bring this behaviour back into line and restore the "natural" order you turn up the heat by going out of your way to offer sugary goodness or wheaty wows or whatever the abandoned habit may be (crack-pipe anybody?).
We are at a fork, one way lies giving in, returning to the norm (or beyond) or, heaven forbid, they take the other path and stick it out. Now we have a problem. Somebody is using their own initiative, their own will, their own drive, to better themselves. Dude, WTF?! Why a problem? Well, I mean, who do they think they are? Seriously, chances are that they are achieving, little by little, something that we want to but have not. Or, perhaps more generally, they are achieving something and feeling better about themselves/life and misery loves company!
We may look interested and ask them about it. Piqued by the enthusiasm we trot out some
"No, come on, what?"
"Well, it's just that I read/heard that's dangerous/bad for you/not what you think it is."
Little seeds of doubt, intentionally or accidentally scattered but often with the result of dragging people back into line. Survive that and you are either the slightly oddball (with sufficient money you get an upgrade to "eccentric") character who lives on the outer bounds of the group's territory. Or, having changed, it becomes time to move on, to find a new pool who share values, code or approach more closely mirroring your own.
Trying to take others with you is a hiding to nothing. It's like trying to teach a pig to sing - it achieves nothing and annoys the pig. When they are ready, they will ask for your help, guidance or input. And even then there is no guarantee that they will follow it. You cannot force it. Over time, you may well forget your own experience but chances are that it was not plain sailing. You can but use that experience to offer guidance, and as is very likely, to help them find a way out when they wander down the same cul-de-sac. Or in a similar vein, while I am not big on scripture - a prophet in his hometown will always be Joe's boy, the Chippie.
We expect the travel to be difficult but we also expect that friends and family will support us. So often we do not see the subtle pressure on the helm, the magnet by the compass. Be strong but be alert.