How the Stomach Works

[TromboneAl]

In researching acid reflux, I realized there's something I don't get about how the stomach works.

When I read about the stomach, the general info says that food stays in the stomach for about five hours while it's physically and chemically broken down. It's then passed into the small intestine.

Makes sense, right?

But let's say that after 4.5 hours, you eat a piece of chicken. So now, you have these chunks of undigested chicken in there with the food that's been broken down.

What happens then? Does the stomach wait another five hours? Is the undigested food filtered out by the pylorus?

 

[Meadbh]

Al, I don't know where you are getting your information from, but here is a peer reviewed study that shows that the median (50th percentile) lag time was 18.6 minutes, and gastric emptying half time was 68.7 minutes. Two hours after eating, only 16.3% of the meal remained in the stomach, and by four hours, only 1.1% remained.

Normal Solid Gastric Emptying Values Measured by Scintigraphy Using Asian-style Meal:A Multicenter Study in Healthy Volunteers

There's a reason why mealtimes have evolved to be approximately four hours apart.

The stomach works by secreting hydrochloric acid on the food and making a chemical slurry out of it.

 

[athena53]

I would guess that there's some sort of filter or small opening from the stomach to the small intestine so that the piece of chicken you just ate wouldn't make it through- it would need more time for the digestive juices to break it down.

 

[Meadbh]

I would guess that there's some sort of filter or small opening from the stomach to the small intestine so that the piece of chicken you just ate wouldn't make it through- it would need more time for the digestive juices to break it down.

There isn't.

 

[braumeister]

There isn't.

Of course not. I thought everyone knew that it's a version of Maxwell's Demon, who stands in the pyloric canal and decides what food items have had enough processing in the stomach to be admitted to the duodenum.

You can train your demon to be more lenient and allow the GERD-inducing items to pass through before bedtime, but it takes patience and perseverance.

If interested, you can PM me and I'll tell you how to order my instructional DVDs that show, step-by-step, the necessary training regimen. Guaranteed to work, and available at a reasonable cost for a limited time only. Prices will go up at the end of this month, so order soon!

 

[O2Bfree]

Apparently the small intestine continues to break down the food:

http://www.webmd.com/heartburn-gerd/your-digestive-system

Small Intestine
Made up of three segments, the duodenum, jejunum, and ileum, the small intestine is a long tube loosely coiled in the abdomen (spread out, it would be more than 20 feet long). The small intestine continues the process of breaking down food by using enzymes released by the pancreas and bile from the liver. Bile is a compound that aids in the digestion of fat and eliminates waste products from the blood. Peristalsis (contractions) is also at work in this organ, moving food through and mixing it up with digestive secretions. The duodenum is largely responsible for continuing the process of breaking down food, with the jejunum and ileum being mainly responsible for the absorption of nutrients into the bloodstream.

But it seems like it'd be best to avoid eating between meals to make sure your food gets digested as completely as possible. So is it really wise to eat more frequent, smaller meals throughout the day, as some nutritionists propose?

 

[audreyh1]

What about when the stomach is slow to digest? Seems like sometimes stomach emptying can take much longer.

 

[kaneohe]

There isn't.

Does the solid chunk of chicken get stuck at the low point of the stomach?
http://www.medicinenet.com/image-collection/stomach_picture/picture.htm

 

[msieweke]

@audreyh1 - Stomach emptying is partially dependent on fat. If you eat a fatty meal, expect the stomach to empty more slowly.

@O2Bfree - Current research indicates eating less often is more healthy. The popular term is "intermittent fasting" if you want to look it up.

 

[Meadbh]

Does the solid chunk of chicken get stuck at the low point of the stomach?

The muscle at the far end of the stomach is called the pyloric sphincter. When the chunk of chicken (or whatever) has been churned and digested into a slurry called chyme, the pylorus opens, the stomach muscle contracts (peristalsis) and chyme is squirted through the pylorus into the duodenum, which is the first part of the small intestine.

In babies, there is a common condition called pyloric stenosis, in which the pyloric sphincter is overactive and fails to relax. It presents at a few weeks of age. The baby's stomach does not empty after a feed. Typically, during the next feed, the now over full stomach contracts, but is unable to overcome the pyloric obstruction. The baby then has a projectile vomit (which shoots milk forcefully across the room). This condition is easy to diagnose and treat with a minor surgical operation.

 

[Walt34]

In babies, there is a common condition called pyloric stenosis, in which the pyloric sphincter is overactive and fails to relax. It presents at a few weeks of age. The baby's stomach does not empty after a feed. Typically, during the next feed, the now over full stomach contracts, but is unable to overcome the pyloric obstruction. The baby then has a projectile vomit (which shoots milk forcefully across the room). This condition is easy to diagnose and treat with a minor surgical operation.

I had this condition at three weeks of age. But in 1950 it was major surgery and (according to my parents) had a 50% survival rate. There is still a huge scar across my upper abdomen from it.

The symptoms you describe match exactly what my mother told me about it.

 

[aja8888]

I had this condition at three weeks of age. But in 1950 it was major surgery and (according to my parents) had a 50% survival rate. There is still a huge scar across my upper abdomen from it.

The symptoms you describe match exactly what my mother told me about it.

Walt, how do you explain that scar to your friends at the pool?

 

[Meadbh]

I had this condition at three weeks of age. But in 1950 it was major surgery and (according to my parents) had a 50% survival rate. There is still a huge scar across my upper abdomen from it.

The symptoms you describe match exactly what my mother told me about it.

Walt, I'm glad you made it! I'm surprised at the 50% survival rate your Mom was given, because this surgery has been around since 1910 and is quite simple. I have never seen a death associated with this surgery. Nowadays it can be done by laparoscopy (keyhole surgery). Certainly, anesthesia has come a long way since 1950, so perhaps that is the reason for the high mortality rate you heard about. Or perhaps you were diagnosed late, when your condition was very ill. Nowadays, it is easy to make the diagnosis early with ultrasound.

 

[Walt34]

Walt, how do you explain that scar to your friends at the pool?

I tell them I was in knife fight and killed the other guy.

 

[Walt34]

Walt, I'm glad you made it! I'm surprised at the 50% survival rate your Mom was given, because this surgery has been around since 1910 and is quite simple. I have never seen a death associated with this surgery. Nowadays it can be done by laparoscopy (keyhole surgery). Certainly, anesthesia has come a long way since 1950, so perhaps that is the reason for the high mortality rate you heard about. Or perhaps you were diagnosed late, when your condition was very ill. Nowadays, it is easy to make the diagnosis early with ultrasound.

I figured it was considered "minor surgery" by now. When I was interviewing for a job one of the interviewers asked if I ever had surgery and I told him about that one. He mentioned that a son of his had died from it (or the surgery) but the year of the interview was 1972 so I think that would have put it about twenty years before, or early 1950's. Maybe anesthesia was really rough on babies back then. I have no idea.

 

[Music Lover]

I tell them I was in knife fight and killed the other guy.

...with his own knife after you pulled it out of your stomach

 

[TromboneAl]

Al, I don't know where you are getting your information from, but here is a peer reviewed study that shows that the median (50th percentile) lag time was 18.6 minutes, and gastric emptying half time was 68.7 minutes. Two hours after eating, only 16.3% of the meal remained in the stomach, and by four hours, only 1.1% remained.

Normal Solid Gastric Emptying Values Measured by Scintigraphy Using Asian-style Meal:A Multicenter Study in Healthy Volunteers

There's a reason why mealtimes have evolved to be approximately four hours apart.

The stomach works by secreting hydrochloric acid on the food and making a chemical slurry out of it.

Yeah, but that's an Asian Style meal. Everybody knows you get hungry again thirty minutes after eating at a Chinese restaurant.

Ha ha, but yeah, I was probably off a bit. I guess the answer is "it's complicated." Here's one reference:

 

[NW-Bound]

Al, I don't know where you are getting your information from, but here is a peer reviewed study that shows that the median (50th percentile) lag time was 18.6 minutes, and gastric emptying half time was 68.7 minutes. Two hours after eating, only 16.3% of the meal remained in the stomach, and by four hours, only 1.1% remained.

Normal Solid Gastric Emptying Values Measured by Scintigraphy Using Asian-style Meal:A Multicenter Study in Healthy Volunteers...

We went to a steakhouse for dinner last night. I ordered a 14-oz ribeye, and my bride a 12-oz filet. I helped her with a couple of ounces at the end.

I think a lot of it stayed in my stomach till past midnight. Or at least it felt so. I don't think I will eat a steak like that again. When I was younger, I would do a steak twice a large and did not flinch.

Have you watched competitive eating? I once caught a segment while channel surfing and watched it totally mesmerized. There was this petite woman who ate a huge amount of food. I looked her up later and found that she was but 5' tall and weighed in the low 100 lbs. She could eat 180 chicken wings, or more than 10 lbs of lobster meat (shell not counted), or more than 60 eggs, in a matter of minutes, in separate competition events. There are competitions like that all over the world, and she would eat huge amounts of pasta, pizza, whatever they put in front of her.

I want to see an X-ray of her stomach afterwards. How long does the food stay there? How long until she needs to eat again?

 

[NW-Bound]

OK, found a photo of her. In this competition, this 100-lb woman beat a 400-lb guy in turkey eating. Her name is Sonya Thomas, an American of Korean descent.

If you think you understand how the stomach works, you need to study this woman.