The amount of posts assuming bad of OP just because she became healthier and then actually defending that abusive a$$hole of a husband (as if going vegan justified being spoken to this way, by your own family, in public) is simply awful. Constant negging and mocking is abu$e.
Few years after marriage I gave up gluten dairy white sugar, to address some chronic medical issues I had. Obviously, my husband didn't divorce me because of this, nor did he sneer or mock me for choosing to make positive changes in my life. He was my biggest champion. We talked about it and worked around it - like how we did when he wanted to give up a high paying job for a less paying one, and move to the suburbs... isn't this how a marriage works?
I never asked him to change his diet for me, but some things I cooked for myself, he sampled and enjoyed them, since anyway the taste remained the same (for eg, using vegan yogurt instead of greek, for tenderising chicken). When we want to go out, we research and pick restaurants that cater for both our dietary choices. If he has bread, I will choose rice. If he has ice cream, I will have a sorbet. It's so easy to work with this with a little forethought and homework.
My husband never gave up on the stuff I gave up (nor did I want him to), he enjoys mcdonalds too much for it but not even once did he criticize my choice; in fact he also learned a lot about the GF-DF-WS lifestyle. Even when I slip up, he'd call the waiter, ask for what kind of sugar is in the otherwise gluten-free, dairy-free dessert and says, "Wait, this was made with brown sugar which basically has the same GI index as white sugar. I will have this, but can you pls make this same pudding with honey or stevia, for my wife?"
This is how people committed in marriage treat each other. With kindness and decency.
OP, congrats on achieving positive things in your like. I hope you also understand that your marriage is as good as over unless you go back to being the sad, insecure, weak person you were before. That's the person your husband married and he will not tolerate the new you, he will keep becoming nastier and nastier because the new you doesn't serve the original purpose for which he married you, whatever it is.
And the way he talked to you in front of his mother, it's INEXCUSABLE. When a spouse starts humiliating you in front of others, it's as good as over. The ball is now in your court - you need to decide whether you deserve better than this, or if you are going to "tolerate" everything for the sake of your kids, lifestyle, whatever.
Sorry if I sound all gloom and doom, but really, anybody - least of all, your husband - who is not happy for you when you are happy, is not good for you.
Marital therapy, if you find the right therapist and can afford it, MIGHT help but ime men like your husband do not change for the better. It's too much hard work for them. They prefer to burn bridges or stay in the same rut, than change.