Once you have swallowed and your food has reached your stomach, how long does it take for it to completely be digested and for your stomach to become completely empty again?
Does it depend on the food?
Are there some foods that are digested immediately and others that will linger in your stomach for longer, or is a meal containing lots of different food just digested all in one go at the same speed?
I got sick recently and I can confirm that there are still some recognizable bits of a Taco Bell meal six hours after I ate it.
Um, the OP said “food.” I’m not sure your example counts 
According to this page from Colorado State University, the times vary on a lot of factors. They did provide some interesting times:
[ul]
[li]50% of stomach contents emptied 2.5 to 3 hours [/li][li]Total emptying of the stomach 4 to 5 hours [/li][li]50% emptying of the small intestine 2.5 to 3 hours [/li][*]Transit through the colon 30 to 40 hours[/ul]
I’m not even sure i know what a Taco Bell is :s
Interesting thank you. Nothing seems to happen immediately then?
[QUOTE=Rhythmdvl]
Um, the OP said “food.” I’m not sure your example counts
According to this page from Colorado State University, the times vary on a lot of factors. They did provide some interesting times:
[ul]
[li]50% of stomach contents emptied 2.5 to 3 hours [/li][li]Total emptying of the stomach 4 to 5 hours [/li][li]50% emptying of the small intestine 2.5 to 3 hours [/li][li]Transit through the colon 30 to 40 hours[/ul][/li][/QUOTE]
How then, based on these numbers, can I erm, “recognize” things I had for lunch (that I hadn’t eaten previously unless weeks prior) in the span of a few hours?
/not a whoosh, just curious
Again, the list was averages—the main thrust of the linked page was describing why the question is hard to answer. Also, consider that if it’s an average of 2.5–3 hours for half the contents to leave the stomach, that means that four to five hours there’s still a bunch of stuff left in there. I don’t suspect the curve is linear, but half a chicken ‘n rice dish is still a lot to recognize after a purge. Lastly, I bet the above times are for a well-functioning digestive situation. Eat something that gives cause to give it back, and it may be likely that there are other things at work keeping the normal process from taking place.
There’s also the other end of the spectrum. I don’t want to devolve into TMI-achusetts, but I’ve seen things that made speedy trips through the digestive system without necessarily having unusual catalysts.
I think it not only prudent, but apropos to mention that I’m mainly talking out my ass—most of this was just found via Google. IANAD
The stomach doesn’t do much real digesting of food at all. Digestion in this sense means the breaking down of proteins into amino acids, carbohydrates into simple sugars, and fats into fatty acids. Those are the components of food that can be moved through the barriers in the intestines into the blood stream.
The stomach serves mostly to break coarse food into a semi-liquid stream (called chyme, pronounced with a “k” sound) that will move easily through the intestines so that the enzymes can work on the particles to digest them. The hydrochloric acid in the stomach serves to break down the structure of food and also to activate the pepsin enzyme, which helps digest proteins.
Peristaltic waves move through the stomach at about a rate of three per minute. These squeeze out any liquids that can slip easily through the pyloric valve into the duodenum, the first section of the small intestine. Water, and other beverages that are mostly water, can start moving out of the stomach almost immediately, although the amount that will go through the valve at any one moment is small enough that even a glass of liquid will probably take an hour to leave the stomach entirely.
It can take several hours for all the food to empty, by which time you’ve probably added more food. Your stomach is therefore working all day long.
If you swallow someone that’s not digestible it will sit there until the stomach can squeeze it out, assuming that’s possible.
But I still don’t get this. How are you recognizing these “things”? Where are they coming out and in what form? If you mean seeing whole kernals of corn in the stool, then it’s simply a matter of their being small enough to be carried through and nothing much interacts with them because they’re indigestible. They’re the neutrinos of the digestive tract. 
What about glucose, sacarose and starch guys? How long does it take from the moment it enters the stomach to the moment it goes to the blood?
Corn, yes. Peas, yes. Lettuce, yes. Hot peppers (ow), yes. How can they make the trip in one hour (and I am not joking about the timeframe.)
Sugars are digested in the small intestine.
Other than that, it depends totally on what food the sugar is hidden in. Sugar in a liquid, like soda pop, will travel to the small intestine fairly quickly. Sugar in solid foods like cake will take longer to get there and have a longer transit time through the intestines. The bigger the meal, usually the longer the transit.
Transit time also varies significantly from individual to individual. That’s why the figures **Rhythmdvl ** quoted were averages with large variables. FourPaws, your system is your system. I can’t predict anything about any individual.
Ha. We were just having this discussion this week.
My B-I-L swears that whenever he eats beef, he has to leave the table by the end of the meal to … um … poop.
I call bullshit. Nothing, in my uneducated opinion, can enter your mouth and exit your bottom in less than an hour.
It’s called the gastrocolic reflex. It’s normally a regulator signal sent out from up the digestive tract to the colon, keeping the colon active and food moving.
In some people, especially those with IBS, the signal is much more violent at times and the spasming can cause diarrhea within a few minutes of food being eaten. What leaves the colon is food from earlier meals many hours before, with no relation to anything that’s just been taken in. However, that’s not the way it feels, says someone who has it.
Check the graph at the link I gave if you want to see something that will make your hair stand on end. (Not necessarily recommending any therapies on that page, but the graph and explanation are good.)
There are a very few people with a condition called rapid transit, in which the time for food to exit is cut unbelievably short, but IBS is more likely since rapid transit affects every single thing you eat.
you alright Exapno? are you still having nightmares about Jonah?
Nightmares? I had a whale of a good time.
Lets say it’s not hidden at all. That you ate pure glucose. How long would it take?
I think it has to do with glycemic index, the higher GI the faster it goes to the blood. Glucose is on the top, so it should go fast, on the other hand, white bread is also close to the top, which i don’t get since it’s a solid, and it has to go from starch to maltose to glucose.
What do you call if he eats chicken?
As this Wiki page shows, white bread has a much lower GI than glucose, 140 to 100 when white bread is used as the reference. That page also has a graph for blood sugar increase times.
Note that the reference index is also an average of different peoples’ response times, so we’re still talking about approximations that doesn’t necessarily apply to you as an individual.
Why does white bread break down so fast? It’s the nature of the carbohydrate.
It’s a fast food restaurant that serves tacos and other “mexican food.” I guess you folks over in the UK don’t have any. Don’t worry, you haven’t missed anything.
Ah I see. No we don’t have them, or anything close come to think of it.