White strings in stool

I am having a diarrhea diet.And it got better i mean its look like poop not just water anymore.But today i found 1-2 cm white string like things (not moving) in my stool. I just wondered what caused them ? Anyone have an idea ? 

P.s: I just started to eat banana for the first time in my life. Does it cause white string like things in poop ? The white strings are few in number i mean they are about approximately 10-12.

Sounds like the stringy bits you get on bananas when you peel them especially since that’s what you have just eaten.  It may not have digested properly if you are not used to eating them.   The other possibility is mucus.   I would stop eating bananas to see if the problem goes away.  If it doesn’t clear up even after avoiding bananas, see your doctor. Give it a week.