I started doing Brazilian Jiu Jitsu. As a result, I drink way less, I'm in a better shape, and can defend myself. I know that drinking will have a negative impact on my performance and that is enough to keep me away from booze. I've also noticed that refusing to drink in a social setting is way easier, both for me and the social group I'm in.

It doesn't have to be Jiu Jitsu, it can be exercising in general.

Hope it works!