As I find myself weakly staggering out of a 4-day bout with the stomach flu, I feel compelled to drag myself in here and find out what the fuck is going on in my body. Consider this a quest for information and comprehension, wrapped in the guise of an invitation to a gross-out competition.
Let me put this as delicately as possible: now that the flu has morphed from the “Ball of Fishhooks” pain in the stomach to the “Fountains of Effluvia”, it brings to mind something I have always wondered about. How long does it take for food to be transformed from what goes in to what goes out? I had two and a half days of nothing but club soda and Alka Seltzer, so I know there was nothing but liquids in there. During that time, nothing but liquid came out. When I finally tried food, I tried a piece of toast and later one graham cracker. About 2-3 hours later, poo ensued, and the stomach pain returned. Did my body really process that food that fast? The stomach pains and raw throbbing sphincter discouraged me from food for another day. Then yesterday I had a bowl of soup and a few saltines, and 2-3 hours later again, I was in agony with the galloping clangs for at least 30 minutes. Does the body really make that much of a change in its fuel that fast? It seems to me there have been times I’ve eaten soup and vomited a couple hours later and seen noodles floating in the bowl. How long does it really take the body to process solid food? I’m getting really hungry, but I have got to get a full day in at work, and I don’t know what to eat, or even if I should.
Yes, it can work fast. That is the pain and cramping: your body pushing things along hard and fast.
nitpick: stomache ‘flu’ …the flu is a respiratory viral infection. You have another infection or food poisoning.
Huh. I had suspected that I had food poisoning from some questionable halibut Sunday afternoon, but I changed my diagnosis to flu when it lingered so long. Food poisoning can mess you up for that long?
Heck, food poisioning can mess you up for the rest of your life, if you’re very unlucky. 
And it could be a short time too.
There is no such thing as stomach flu. Flu (or influenza) is a respiratory illness with the following symptoms:
[ul]
[li]high fever[/li][li]cough[/li][li]muscle aches[/li][li]weakness[/li][/ul]
There are many bacteria and viruses that can cause your symptoms, but none of them is the influenza virus.
As for how long it takes the body to process food, my experience is that a G.I. infection can cause things to pass much more quickly than normal.