High Fiber?

I have had my Thyroid removed since I had my RNY and am finding it extremely difficult to get the scale to budge.. I have been reading about thyroid issues related to dieting and that High fiber will help.. Do you think it could hurt me.. to drink high fiber drinks before I eat..similar to the water loading we were taught in the start of this whole process.
I am 4 yrs out of my RNY..
I need to get the excess weight off that came on when I had the thyroid removed and the Dr has given me no answers except to keep dieting and exercising but seriously this is getting my very depressed.