Could 10 day digestive tract processing cause my gut problem?

[ozguy914]

I have had severe, undiagnosed gut disease for about 25 years.
I recently learned that the average mouth to anus digestion time is about 50 hours.
My time was 8 days until I was ~50yo, since then has been 10 full days.
The stages I go through are always consistent, but for brevity will not add them at this stage unless asked.

So could it be that after three days the digested food simply festers or rots in my colon for 7 extra days because I have an extremely slow digestive system?

As I, like so many other sufferers, react badly to almost all foods, it makes sense that I'm not allergic to them, they're simply not supposed to hang around so long.

How could we test the throughput rate from mouth to bowl?

And is there a condition already known such as 'sleepy bowel syndrome'?

Please comment all you can, and I'll be back to check everyday.