Or... you could use artificial sweeteners.
But they will of course effect the flavour of the beverage. If you are talking beer, I actually suspect that it might work out pretty well, because you aren't actually looking to make it "sweet" sweet... just to enhance the sweetness thats already there.
If you are after a sweet cider or perhaps a ginger beer or something where you really want it to be properly sweet... then I suppose it will all depend on whether or not you are OK with the taste of artificial sweeteners; and which artificial sweetener you use.
For instance, I never liked diet coke, could pick it a mile away and didn't like it at all, but coke zero, now that stuff is fine with me. It doesn't taste artificially sweetened to me at all.
Mind you, the disclaimer to this post is that while I drink a LOT of soft drink, a naturally sweetened one has not passed my lips in at least 3 years. It might be (probably is) me getting used to it, but IMHO I feel that the latest versions of artificial sweeteners are much more palatable than the old ones.
I have no input whatsoever on which ones you could use or how much to use etc; but I certainly wouldn't rule them out if doing the things that newguy suggests wont solve your problem
Thirsty