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Warm water

arthwollipot

Observer of Phenomena, Pronouns: he/him
arthwollipot
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I've heard that you should always drink lukewarm water. If you drink cold water, the body has to expend energy to warm it up so that it can be properly absorbed. You urinate less often because the water is more efficiently absorbed by the cells when the water is warm.

This sounds like a load of rubbish to me, although I have heard a similar thing from a paediatrician. He said that it "lubricates the bowel" though, so the stories are not exactly the same.

Discuss.
 
arthwollipot said:
I've heard that you should always drink lukewarm water. If you drink cold water, the body has to expend energy to warm it up so that it can be properly absorbed. You urinate less often because the water is more efficiently absorbed by the cells when the water is warm.

This sounds like a load of rubbish to me, although I have heard a similar thing from a paediatrician. He said that it "lubricates the bowel" though, so the stories are not exactly the same.

Discuss.
Click to expand...

I'm no physician but I think the first one makes some sense, heating stuff does require energy, but it doesn't need to be heated to be absorped it needs to be heated because your body likes being 37 degree celsius..

Being more efficiently absorbed, would require the water still being cold when it reaches your kidneys to make any difference that sounds like nonsense.

Lubricating the bowels, I have heard that one before sounds wooish put this way, but it does seem to work to take some warm water when obstipated, but that could very well be confirmation bias.
 
I suspect that the "lubricating the bowels" bit is an incorrect logical conclusion derived from the fact that lack of water in the body, say caused by sweating from severe overheating, can lead to constipation and slower peristalsis.
 
Lets assume:

The average body has a mass of 75 Kg
The content of a glass of water is about 0.3 Kg
The average body about 37 celsius
The average cold glass of water is about 15 celsius
The average warm water is about 25 celsius

This makes the ratio in mass 100 : 0.225 (or 1 : 0.00225)

Lets also assume that the heat exchange ratio between water and the human body is the same. By ingesting the glass of water, the water and the human body can quickly exchange heat given that the water is completely surrounded by the much large human body.

After drinking the cold glass of water, the body becomes 36.91 Celsius ((75x37)+(0.3x15))/75.3)
After drinking the warm glass of water, the body becomes 36.95 Celsius ((75x37)+(0.3x25))/75.3)

A whole whopping difference of 0.04 degrees Celsius...
 
Well unless you are underweight to start with, why would you worry about drinking cold water causing you to expend a few calories?
 
Now, let me add another line of woo reasoning: food separation.

When you combine foods (e.g. meat and rice) your body will expend more energy to digest them. So, you will compensate by eating more and you will end up fatter, although you expend more calories.

If you drink more cold water, you will expend more calories, so you will eat more to compensate for this and end up fatter.

So, people who drink cold water with their steak and mashed potatoes will be fatter than people who drink a lukewarm glass of water, eat the steak first and and the potatoes an hour later.

Go figure...
 
I think this is, essentially, the basis of the Atkins Diet, but that, supposedly, has the opposite effect! I just loved eating the burgers and sausages out of curiosity. Oh well, in the gym again tonight!
 
Broes said:
Lets assume:

The average body has a mass of 75 Kg
The content of a glass of water is about 0.3 Kg
The average body about 37 celsius
The average cold glass of water is about 15 celsius
The average warm water is about 25 celsius

This makes the ratio in mass 100 : 0.225 (or 1 : 0.00225)

Lets also assume that the heat exchange ratio between water and the human body is the same. By ingesting the glass of water, the water and the human body can quickly exchange heat given that the water is completely surrounded by the much large human body.

After drinking the cold glass of water, the body becomes 36.91 Celsius ((75x37)+(0.3x15))/75.3)
After drinking the warm glass of water, the body becomes 36.95 Celsius ((75x37)+(0.3x25))/75.3)

A whole whopping difference of 0.04 degrees Celsius...
Click to expand...
This all assumes you do not generate any more heat whatsoever during the drinking phase of the experiment!
 
Water has a heat capacity of about 4 Jg-1K-1. Using Broes' assumption of 0.3kg for a glass of water, that means the energy needed to heat up a glass of water from 15oC to 37oC is 300*4*17 = 20,400J = 5,100 Calories. The labels on food are actually in kJ and kCal. According to the bag of crisps (possibly chips if you're American) next to me, one 35g bag contains 752kJ. That means that to replace the energy used in heating a glass of water you would need to eat approximately one crisp, possibly less. Don't plan on losing weight by drinking cold water any time soon.
 
Cuddles said:
Water has a heat capacity of about 4 Jg-1K-1. Using Broes' assumption of 0.3kg for a glass of water, that means the energy needed to heat up a glass of water from 15oC to 37oC is 300*4*17 = 20,400J = 5,100 Calories. The labels on food are actually in kJ and kCal. According to the bag of crisps (possibly chips if you're American) next to me, one 35g bag contains 752kJ. That means that to replace the energy used in heating a glass of water you would need to eat approximately one crisp, possibly less. Don't plan on losing weight by drinking cold water any time soon.
Click to expand...

This doesn't seem right to me. If I heated the glass of water by lighting and burning said crisp beneath it (assuming no heat is wasted) I'm struggling to see how it could raise the temperature by so much. The burning process would probably, I guess, last a matter of seconds only.

I'm probably missing some important aspect of physics, but intuitively, something seems awry. Could it be the Cal to kCal conversion?
 
Southwind17 said:
This doesn't seem right to me. If I heated the glass of water by lighting and burning said crisp beneath it (assuming no heat is wasted) I'm struggling to see how it could raise the temperature by so much. The burning process would probably, I guess, last a matter of seconds only.

I'm probably missing some important aspect of physics, but intuitively, something seems awry. Could it be the Cal to kCal conversion?
Click to expand...

I've bolded the important part.
 
Southwind17 said:
This doesn't seem right to me. If I heated the glass of water by lighting and burning said crisp beneath it (assuming no heat is wasted) I'm struggling to see how it could raise the temperature by so much. The burning process would probably, I guess, last a matter of seconds only.

I'm probably missing some important aspect of physics, but intuitively, something seems awry. Could it be the Cal to kCal conversion?
Click to expand...

You are underestimating how much heat is lost when you burn something underneath a glass or pan etc...

Try to pretend it completely burns inside the water... there are still significant losses, but I think even intuitively you can see this would yield a larger heat gain...
 
OK - I thought it would be something like that. Just shows you eh how much energy we must waste!
 
On a quick google, I found the following doozy:

Drinking hot water after meals reduces cancer risk. Let me explain how. Drinking cold water will solidify the oil part of the food we have eaten. This will slow down the digestion process. And when this sludge reacts with the digestive enzymes and acids, it will break down and will start getting absorbed by the intestine faster than the solid food. This lines the intestine. The consequence is that this will turn into fats and lead to cancer. Therefore it is best to drink hot soup or warm water after a meal.

Cold water can also in extreme circumstances lead to heart attacks. As we have our meals enzymes and acid secretions start and this process sort of warms up the body. Drinking cold water is like attacking the body with an exactly opposite temperature. Not only does the whole procedure of digestion gets interrupted or slows down, the body can also react in the form of a heart attack. It does not always come after a pain in the right arm or pain in the chest.
Click to expand...

http://www.healthoma.com/a-glass-of-hot-water-after-meals-reduces-cancer-risk/
 
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