I’ve always heard that caffeine and alcohol dehydrate you. I know that they are diuretics. I know that when I drink soda, I often will feel thirstier after I’m done drinking it than I did before.
If you were stuck in a place without water, and all you had was a caffeinated beverage to drink, would drinking it cause you to die of dehydration quicker, or would you be able to get some hydration out of it and drink it indefinitely?
I haven’t drank water in years. I drink about a gallon of iced tea per day, along with the occasional Pepsi. I haven’t noticed an ill effects, though others express horror when I tell them this.
The diuretic effects of caffeine are quite miniscule compared to the amount of water in soda. (It’s something like 98% water, after all.)
I’m not sure about alcohol.
Sea water is 96-97% water, and if that’s all you have to drink, you’ll die.
All I know is, if all I had was Pepsi or beer, I’d either die or wish I was dead. Either one makes me thirsty as hell.
Sea water contains salt, which is much more of a problem to the system than caffein or alcohol.
Back before pasteurization, the only thing safe to drink was either coffee or something alcoholic. People in New England in the 1830s drank nothing but hard cider (even children – water wasn’t safe). They didn’t die of thirst in the summer, so you wouldn’t, either.
As far as the alcoholic beverages go, I would guess that it depends on how strong the beverage is. Beer is pretty weak and probably has more than enough water to make up for the dehydration caused by alcohol. On the other hand, I don’t think you would live very long off of vodka. I’m no biochemist however.
I presume they all died of something else before cirrhosis of the liver got to them, right? Or our knowledge of such things was so poor we didn’t connect alcohol with dying a certain way.
The Lancet had a case report a few years ago involving a man who drank nothing but tea every day, 4 liters a day, and apparently had done so for years. He ended up in The Lancet after switching from plain black tea to Earl Grey; bergamot oil, the flavoring in Earl Grey, contains a compound which is a potassium channel blocker and can cause nervous system dysfunction if you drink Earl Grey at the rate of 4 liters a day for 2 weeks or more. The case is a great example of the saying “The dose makes the poison.” In any case, the tea per se didn’t cause any problems (or none that he complained about, anyway).
The short story “Wine on the Desert” by Max Brand is about a gunslinger bad guy out West. Near the Border. He rides up to a rancho and orders the Mexican hired hand to fill his canteen. Then rides off into the desert to evade the law.
Once he’s well into the desert he opens his canteen to find it filled with wine. In that moment he knows he’s a dead man. The Mexican had used wine on purpose to cause his death.
So what’s the science behind this? Max Brand appears to have taken it as axiomatic. He wrote the story in 1936.
I drank virtually nothing other than Coca Cola and beer (but by far mostly Coca Cola) when I was in college and I’m still here.
I don’t believe cirrhosis was an issue. The cider they drank each day was low alcohol (it could be distilled into something stronger, either by heating or – more common in New England – by freezing, but that wasn’t their everyday drink).
Contrary to 21st century mythology, undistilled alcoholic beverages are not all that dangerous to drink. Watered down beer has been fed to babies over the centuries if their mothers couldn’t produce enough milk, and there are plenty of countries where you still have people drinking a glass or two of wine or beer each day with not adverse affect on their health. People demonize alchohol to a ridiculous extent these days (mostly due to fear of drunk driving), but it’s not as bad a beverage as they concern (people in 1830 were less likely to drive drunk, for instance*).
OTOH, water is not the miracle beverage people think. Again, in the 1830s, no one would dare drink water – it was too likely to be contaminated. And these days, dehydration is pretty much an irrational fear.
*They did, only they were driving horses, who had more sense than a car. Still, there were accidents, but you did not go driving every day.
I will go weeks without drinking anything other than Diet Coke, tea, and coffee, and I seem to be plenty hydrated. And fairly healthy for a diabetic of 25 years. I tire very much of the myth “you actually need MORE water when you drink coffee/tea/soft drinks; you would die of thirst if that was all you had to drink!”
One of greatest peeves is being told that “caffeinated beverages don’t count” when it comes to how much you drink. For some reason, the nurses at the clinic I go to are the worst about this. My best friend went in once and they asked her how much she’d had to drink that day? She replies, 5 or 6 glasses of iced tea. They proceed to tell her that caffeine dehydrates you so much that it cancels out the water in your tea/soda, and that you need to drink 8-10 glasses of water on top of that, like the tea had never happened.
She looked the woman in the eye and said, “Then I haven’t had anything to drink in months and should certainly be dead.”
I am adding myself to the ranks who say you can live fine off fizzy drinks and coffee as your only liquids just fine. I say this from personal experience as one of my eccentiricities is that I dont trust tap (unboiled) water but dont feel bottled water is value for money. Therefore, liquid wise, I live on diet coke, cappiccino’s and normal coffee. If I am on holiday I may treat myself to orange juice but thats about once a year.
if you read the labels on the fizzy drinks a huge percentage of the ingredients are basically water and as a prvious poster pointed out whilst this is true also of sea water the difference is the remaining ingrediants a not comparitively as harmful. So damn science on this one 
There’s someone on this very board who (if I recall correctly) claims to drink only beer. Can’t remember who it is, but the claim was made in a thread very much like this one.
Here is the thread; Larry Mudd claims to have drunk only beer and coffee for an extended period.
You know, that sounds worse than it is when you see it in black-and-white.
There are hundreds of millions of Chinese who only drink tea. My father in law drinks 24 oz of beer for breakfast, lunch and dinner, and drinks tea inbetween. He’s in his 70’s and been doing this for the 15 years I’ve know him.
There’s a cut-off effect with moderate (but regular) doses of alcohol or caffeine, so the body won’t de dehyrated below a certain level.
A friend who is a professional brewer informs me that beer isn’t that diuretic below about 4.3% ABV, so you could quite happily exisist on nothing but weak alcoholic beverages, and people often did when water supplies were unsanitary.
Just like to add myself to the list of tea-only survivors. 
My typical daily fluid intake is 8-10 mugs of tea, a glass of orange juice for breakfast, maybe a couple of beers or glasses of wine in the evening. I can’t remember the last time I actually drank water on its own.
Oh, I’ll have a Coke if I go to McDonald’s or somewhere like that, but that’s a fairly infrequent occurrence. I don’t drink it at home.