I know this doesn't sound encouraging (bear with me), but I gained 20 pounds in the past 2 years of sobriety because I ate like a pig. Actually, I ate like a 10 year old girl was put in charge of the grocery shopping (nothing wrong with Lucky Charms cereal, though... just not a mixing bowl portion for a snack).
It really does take time for your body to find it's "baseline", so to speak and it doesn't help that it is different for everyone. At the end, I was drunk daily, so I imagined the fantastic weight loss I would have due to the lack of alcohol calories. Unfortunately, the alcohol was replaced with much higher calorie foods! I have only recently started to take the reins again and eat healthily.