Digestion and water

[David_Minh]

So today I got into an argument with my mom's boyfriend about nutrition. He claims that if you drink a large glass of water after eating a meal it will offset the balance of acids in your stomach. While he was preaching to me about nutrition, he was eating a peanut butter bagel after having two egg mcmuffins; I thought he was joking

I told him that the benefits of drinking water after a meal outweigh the "negative" effects of digesting the water with your food. But as I was saying this I was wondering, is drinking water detrimental to your digestion? What are you're thoughts?

[jawadams]

I've heard this as well. Basically the water dilutes the digestive acids so it takes longer to digest.

Vince Gironda said this, and he's a f*cking hero.

When I was cutting once I wasn't drinking any water 30 mins before/after my meals. Had good success, but have no idea if the water thing helped.

[syvnick]

IMO, you shouldn't drink water 30 mins before or after eating a meal. like jawadams said, it dilutes the digestive enzymes in your stomach making it more difficult for your stomach to digest the food. Just drink a lot throughout the day to make sure you don't get thirsty while you're eating.

[David_Minh]

So if the enzyme dilution theory is true, does it outweigh the risk of eating more because you feel less full?

[kingtego]

The release of HCl and enzymes in the stomach is controlled by the volume of contents in your stomach, among other things; more specifically, by the distension caused by food intake. So, if you take in more food/drink, your stomach will release more acid and enzymes. It will still take longer to digest because there is more contents, but the water isn't going to significantly affect the pH of your stomach. At least not in the amounts that people normally drink.


Water dissociates to form a 1:1 ratio of moles of hydrogen ions and hydroxide ions.

Say the concentration of HCl in the stomach is 0.1M, which is a relatively low estimate, according to some sources. This means that the the concentration of OH- is 1x10^-14/[H+]

=1x10^-13

Since water is the only source of hydroxide ions, in this 0.1 M HCl solution, it produces this 1x10^-13 Molar hydroxide ion, and so also produces 1x10^-13 hydrogen ion. The concentration of each of these ions are so insignificant when compared to the concentration of the HCl, that they would have no effect.

Obviously, there are more compounds in your stomach than water and HCl, but purely looking at these two, there would be no effects on pH.

I guess it's possible for you to drink so much water, that the ionic strength of your stomach solution could be affected, which could in turn affect pH, but I would imagine it would have to be a large amount of water that was greater than the amount of liquid already being produced by your stomach, which I read can be up to 4 L in a day.





So no, drinking a glass of water won't affect your digestion.

[LeftyBaseballr]

Actually your body uses up to 7 Liters of water a day. Your Colon (Large Intestines) job is to reabsorb this water. Hence constipation or diarrhea. (Your colon either absorbs too much water or it dosen't absorb enough)

Your PH levels in your stomach are strong enough to dissolve nails so I don't think one glass of water will change the pH that much.

Your stomach is actually just a container that breaks down the food anyway. Most of your absorption takes place in your small intestines. Something that will slow down absorption is fat. The muscles that move down the food through your small intenstine will slow down if there is a large amount of fat in your diet giving it more time to absorb the more difficult to break down fatty acids. (Keeping you full longer)

[cell technical]

Originally Posted by David_Minh

So if the enzyme dilution theory is true, does it outweigh the risk of eating more because you feel less full?

I've read dozens of magazines and websites touting this practice--but not once has a glass of water actually made me feel more full.

[Snaple4]

I usually drink anywhere from 4-8 glasses of water with my lunch or dinner... The more water I drink, the quicker I get hungry afterwards. It makes me feel like I have a bunch of stuff in my stomach but I still feel like eating. If I don't drink any water then I will feel full longer and eat about the same... Sometimes less.

[ralxz]

This is interesting, so does kingtego's response pretty much break the "myth"? I wouldn't mind ditching water while eating if it'll help but it doesn't seem like it's going to do anything