I read about very few people who encountered pain while doing flush (ca 3), and maybe 2 of them think that pain was caused by stone being somewhere inside ducts (stone stuck).
Now, 2 people is far to little to make any conclusions, and certainly too little to answer your question.
But, going non-fat for a few days can for sure create stronger reaction inside liver-gallbladder and may result in larger number of stones.
BUT, be aware, that non-fat or low-fat diet is No1 cause of gallstones.
Low-fat diet will cause bile stagnation, and bile stagnation is very important factor in Gallstones formation, and Gallstones growth.
I would recommend to every person suffering Gallstones attacks, to go on HIGH fat diet, but of course, the FAT should be natural, non-heated, non-processed, non-preserved, non-refined, as fresh as possible!
Good fresh raw (non-heated) foods (They are only good if you can tolerate them - if they don't cause an attack ) are:
- raw eggs ( best organic),
- raw cold pressed oils (olive, flax, sesame, walnut, haselnut, sunflower, almond, ...) ( best organic),
- raw cold-smoked fish (salmon, trout, mackrel, ... best wild),
- raw cold-smoked meat (beef, birds, sheep, ... ),
- non-pasteurized home made milk products like sour cream, yogurt, cottage cheese
Avoid fried foods, even fried or baked nuts may cause an attack!
The only preservative used for smoked meat/fish should be unrefined Sea Salt and natural fresh or dried herbs-spices like garlic, tamari soy sauce, miso, lemon juice, cayenne,...