Lately I'm eating too much. As a result I'm so full that when I consider drinking a beer or something I decide not to because I'm too stuffed. By getting fat I'm staving off the vice of drunkeness.
It reminds me of a weight loss scheme a guy once shared with me; spend all your food money on stuff that isn't edible. Some of us can't do right across the board, so we have to pit our vices against one another and hope the lesser evil wins.