Re: How long does the entire digestive process take?

The digestive process can vary depending on what is being eaten and the 
person's metabolism.  For example, fat takes alot longer to digest than 
sugars.  Fiber in the diet speeds up transit time.  Generally it can range 
from 24 to 48 hours for men and slightly longer for women.  Chewing takes 
5 to 30 seconds followed by swallowing for up to 10 seconds.  The food 
enters the stomach where it is churned and broken apart by harsh acids, 
namely hydrochloric acid.  The food can remain in the stomach from 1 to 4 
hours after which it empties in a semi liquid form called chyme into the 
small intestine.  Here is where most of the real digestion takes place.  
In other words most of the nutrients are absorbed from the small intestine 
into the blood stream.  The highly acidic nature of the chyme is 
neutralized by the pancreas with bicarbonates and bile from the 
gallbladder and liver.  This process can take about 3 to 6 hours.  Finally 
about 10 hours after you've eaten the mushy paste of undigested food 
enters the large intestine or colon.  Here it may take another 18 hours or 
even up to 2 days before its elimination as feces.  Water and certain 
vitamins are absorbed from the colon but most of the waste consists of 
indigestible bits of food, mostly fibers from fruit, vegetables and 
grains. 
So you see transit time can vary anywhere from 22 hours up to two days.
References are Under the Microscope Digesting- Angela Royston and Food and 
Digestion by Brian Ward.  Also try: yuck.kids.discovery.com
Hope that helps.