While I am not an expert on gall stones or flushing, I can possibly shed some light.
When you do a flush, there are often 2 kinds of stones. There are green stones that are often an actual product of the flush but may have very small cores that contain real stones, some even microscopic.
The other is the grayish stones, which are the real thing.
The stones are usually held in the gall bladder and are occasionally expelled but the flush can actually cause then to be expelled en-mass, which is why many can be seen at one time.
I do not get where they claim that parasites only feed on meats. They may prefer meats because the meats are more nutritious to them but they are not limited to such. Also, many parasites also feed directly off of us, getting their nutrition out of our blood.
As for sugars, many vegetables will have significant amounts of sugars.