I do recommend everyone reads the fibre article on nutrition wonderland website. Its very information.
Yes 40grams of fibre is more than needed and you are right you should increase somewhat gradually.
My issue might be due to fibre but i think its mainly due to my slow bowel which i can't do much about. But i've been to the loo this morning. Actually TMI coming up. I have just realised that leading up to TOM slows everything down even more. But other people might be so affected. Again its my medication that causes that slowness.
The soluble fibre holds the water so it doesn't need so much extra water, same with vegetables. Its mainly the fibre in bread that needs more water.
Anyway the good thing about yesterday for me was because i wasn't feeling hungry with my tummy pain, i ate a lot less and my weight is down today, though i had a headache during the night and might have been a bit dehydrated too. So this morning i had a little salt. I'm feeling good now.