I'm doing my best to stop drinking, but my local only has Heineken 0 available. What else do you lot drink that I can reliably get in the pub, which isn't full of caffeine or sugar?

Water is about all I can think of but I'm wondering if there is something I can ask for that I'm overlooking. I'm hoping this will be like when I learned about pesto; I couldn't believe I had gone so long before eating it.