I always say "I can lose a couple of pounds but I can't lose a lung or a liver" (in relation to gaining a bit of weight as a result of giving up smoking or drinking)
Losing weight is easily resolved once the bigger issue is dealt with. I combined quitting alcohol with quitting carbs too, because I had put on a lot of weight before I quit. I've lost 30lbs since then.
It'll all work itself out. It's far more important to focus on your sobriety if you can only focus on one thing at a time.