I gained a little weight at first as well (and I certainly didn't need to gain any). But it soon stabilised. Now I'm working a proper program of recovery and my alcoholism isn't 'coming out sideways' (my continuous search for feel-good from outside factors, such as sex, food, buying stuff, as well as the alcohol, has always been an issue to be honest) and I'm not trying to make myself feel better using (abusing) food, my weight has stabilised and I've been able to lose the excess weight that I'd been carrying for the last few decades. I had to do that recovery work first though. My boyfriends mother bought me a birthday gift yesterday while we were out and I needed to get a UK 10. My 12 jeans are starting to get a little loose as well. Not had that since my teens and I'm in my forties now.
I do follow a healthy diet plan, but it isn't one where food groups are cut out, and there are plenty of foods that can be eaten in unlimited amounts (Well, til you're satisfied) and space for (measured) treats each day. It's called Slimming World, but think it might just be in the UK.
Anyway. One thing at a time. Remind yourself of why you DID decide sobriety was a good aim for you - just because others are putting 2 and 2 together and making 7, it doesn't mean they need to affect you. Sobriety and recovery give us lots of things. Eventually. Once they have led us to an altered perspective and our attitude to things has started to change. It is not a quick fix. And just abstaining from alcohol doesn't do it.
While you are starting to kid yourself that sobriety was just a weight loss tool, you're really giving your AV some prime material to work with.
Might be time to refocus. Why did you decide you needed to stop drinking? And what is your recovery plan?
(If you want a weight loss plan, get one, but make it separate from your sobriety. Plus, cutting out food groups at this stage can quickly backfire. Better to find something that is long term sustainable, healthy, and relatively hassle free).