Honestly, I've found so many good reasons not to drink sugary fizzy pop on my own account that I certainly don't like my kids to do it (although they get a pass occasionally).
My main concern with it as a substitute is that you get through it quickly and rack up the sugar levels in no time. Best bet as far as I'm concerned are 0.0% beers - a third of the calories and a fifth of the sugar - although I'll try to stick to two of those at max. They make me feel groggy despite having no alcohol in them.
Personally, I recommend switching to diet ale or sodas. Took me a while to get used to it but once you do, there's really never any reason to go back. And the sugar free stuff is really, for real, sugar free. No calories and no sugar, and you can definitely feel it.
Yeah but why? I see two options: you are (1) uncomfortable with providing the reason or (2) have no problems with that. So I assume we deal with (1) here. But you have many options: instead of drinking sugary liquid that you may not even like and that is not good for your health, you can provide any reason you want, and liver problems is efficient and basically closes a discussion. (Many people won't even want to think about it as they might have bad AST/ALT ratios, too.)
The article does a great job of explaining how alienating for others is dealing with a non-drinker. I won't talk about it explicitly so others are more comfortable in these scenarios, even though I have no problem at all with being sober and talking about it if prompted.
