I know caffeine is not good for your voice or your body in general. I'm just wondering if your drinking caffeine like one diet soda on a day your not singing would it affect your voice the next day? I basically would like to know how long the effects last and if its ok to drink it sometimes?

Well, I don't specifically know the exact amount of time that a caffeinated beverage would affect your voice. What I CAN tell you is this. Jaime might be inclined to disagree but he and I have somewhat different lifestyles.

I've actually found that I NEED a little caffeine in order to sound better. The reason being that I work at an IHOP. I've been a coffee drinker since I was FIVE! If I try to sing without having had at least one cup of coffee that day, my voice suffers. It's not because caffeine is good for your voice, but rather that I'll usually end up getting a headache from the caffeine withdrawals. The trick is NOT to overindulge. When I quit smoking, there were times when my voice didn't sound up to par. My body was simply not used to the lack of niccotine. After a couple of weeks it wore off. I never gave up all of my vices though, and it's OKAY to have a few. While I will say that drinking nothing but water and hot tea are the safest way to go about it, it's hard to do. (Especially considering the crazy hours I work;)

So my inevitable advice would be to allow yourself to have that one caffeinated drink an hour or two before you practice. It might be just enough to set your voice, body, and mind at ease. Just DON'T OVERINDULGE!!!

Aloha!
Well, I drink one cup of coffee as well.
I can`t see any bad results in view of singing.
They say that coffee will dry out your body. But in fact I recently read that this is not that dramatic than a lot people think and pray. They wrote that you can count coffee very well to your daily liquid intake.
Next to the cup of coffee (one cup shall be very good for health) I drink pure water, one glass milk a day, and some aplle juice or orange juice.
I can "work" with it very well.

Try on your own. Anybody is different..

I, too, have been unwilling to give up that little vice ;) But even Jaime himself said in RYV that while he recommends giving them up, if you choose not to then you should definitely increase your water intake to compensate for the diuretic effect. I have taken this advice, and it has worked very well for me.

I avoid everything that has caffeine in it. Coffee gives me rosacea and juices are very acidic too just so you know! Even decaf makes my skin break out My husband also just quit coffee cause it was making him feel too stressed out at work. Also, read the ingredients on a pop drink; groce!!