I was reading that Cecil column, and I wondered if the importance of water was being understated. Doesn’t digestion of carbohydrates involve hydrolysis? as such, doesn’t it have a dehydrating effect on your body? You said that a person can actually eat enough bread to get all the water they need- but I was under the impression that the more bread they ate, the more water they’d need. Can you explain what I’m not getting?
I’ve moved this thread from General Questions to Comments on Cecil’s Columns because it is about this column written by Cecil: Can man live by bread alone? - The Straight Dope
Gfactor
General Questions Moderator
Let’s look at the digestion of starch and then at cellular respiration. Each glucose unit of starch requires one molecule of water to separate it from the parent molecule. It is then used to power the cells, who, with the addition of oxygen, turn it into carbon dioxide and water, six molecules of each. Net. gain: five molecules of water for each glucose unit.
From a kilogram of starch you’d get 556 grams of water.
ah, thanks very much. But if that is the case, and I can really hydrate myself simply with an abundance of carbohydrates, why all the fuss about drinking? and doesn’t experience show that i get thirsty as all hell when i overdo it on the dry starches without water? why does that happen?
Maybe that’s the effect of other ingredients in the bread, like soluble fiber.
Much of the “fuss about drinking” is without any scientific backing. On average, an adult’s body needs about two liters of water a day, which has led to a claim that you should drink eight glasses of water a day. But the claim doesn’t follow, because that two liters includes the water in the food you eat. If you eat a decent diet, you’ll be getting quite a bit of that water already, and need to drink quite a bit less. In other words: eat sensibly, drink when you’re thirsty, and don’t bother with counting how many glasses of water you drink (assuming you’re in average good health).
As to why you feel thirsty when you eat a lot of dry starches - perhaps they contain a fair amount of salt, or maybe they just make your mouth and throat feel dry so you feel thirsty right then even though your body isn’t low on water?
I recommend finding another gauge than “when you’re thirsty.” Thirst is a sign of dehydration, which is already becoming too late.
When your mouth is dry and you’re thirsty, you probably should have drunk some water already.
There are reasons other than being thirsty to want to drink water. I like drinking water when I eat - a sip after every 2 or 3 bites clears the palate and makes the next bites more tasty. Also, the moisture makes each bite easier to chew and swallow.
Do you have a site for that, that’s not one of the “8 ounces of water a day” pages? I don’t have a site for the opposite view, but it makes no sense to me that our natural urge to drink should be so off.
Of course thirst indicates one is at the dry end of the natural fluctuations of fluid and salts in the body, but I don’t think that counts as “dehydration”.
I wasn’t referring to the commercial fuss about drinking x glasses of water a day. I’m healthy, not stupid. I meant the general perception of 6 and a half billion people that it’s necessary to drink at all. Based on what’s said above, and seems reasonable, I shouldn’t EVER need to drink. I eat plenty of carbohydrates, and some of them are even from fruits and vegetables that have high water contents themselves.
Yet experience does not show this to be the case. I get thirsty when i don’t drink. por que?
I work at a Renaissance Faire that performs in June. Trust me, “I’m not thirsty,” is not a safe indicator that you don’t need to drink. Believing that it is can win you a trip to the E. R.
S’truth. Here in the desert hyrdation is our mantra. Whenever somone comes to her house, my sister-in-law always always offers something to drink as soon as they walk in. We were carrying those half-liter holsters more than twenty years ago. I don’t drink the full two-liters a day during the summer, unless I’m outdoors, but it’s easily a liter. Water is your friend, here.
From the Mayo Clinic:
That seems to be a site for my point of view. It states that it’s possible to already be slightly dehydrated. So you’re not necessarily dehydrated if you’re thirsty.
If you’re sweating and losing moisture that way, you should drink even if you’re not thirsty, but if you spend your day in an air-conditioned office you’re not dehydrated if you wait until you feel thirsty before you go to the water cooler.
Admittedly “thirst = dehydration” is a less dangerous simplification than “not thirsty = not dehydrated”, but without a site to the contrary I’ll continue claiming the first is a misconception.
Can somebody please change the title of this thread? It’s driving me nuts.
Either “live by bread alone” or “eat bread alone”, but not “eat by bread alone”.
naita, the point is that the thirst sensing system is not finely calibrated so that it triggers merely while you’re low on water, but rather after you need water badly. If you’re thirsty, then you need to drink, but you probably need to drink before you get palpably thirsty.
You’re probably okay in an air-conditioned office not doing heavy labor if you wait until you’re thirsty to get a drink, but then how do you know how much to drink? 1 glass? Till you’re not thirsty any more? Till you’re so full of water you feel sick? Thirst has a slow response going away as well.
Thanks for helping to clear that up. I wasn’t sure how to respond in a way that could explain it well, but you did.
I’ve yet to see a site confirming that thirst kicks in only “after you need water badly”. Your site from the Mayo clinic says “possible” and “slightly dehydrated”.
Let me repeat my statement that this possible misconception is much less dangerous than the opposite of a lack of thirst always indicating proper hydration, but I’m not disputing thirst’s inadequacy as an accurate indication of a need to drink, or as an indicator of how much to drink. I’m disputing the specific point that “when you’re thirsty you are already dehydrated”, now restated by you, despite the clarification in my previous post, as “after you need water badly.” The one site offered does not support those statements in general.