The French do great research. I am ok to eat bread now, I don't much, but also have no constipation. (I research Dyshidrosis, an allergy to Mycelial Candida) There is another hypothesis that Candida is actually involved in the digestion of cereals. That the pathogenic mycelial form of Candida is failing to do this, hence the celiac or intolerance to gluten, which the yeast candida is hypothesized to digest for the gut, and the allergic reaction to the mycelial Candida.
This covers the leaky gut theory which has serious holes in it, as your gut is designed to be permeable, and the Candida overgrowth theory. It is not an overgrowth of the yeast form, but a growth of any amount of the abnormal mycelial form.
All the above would explain why Faecal transfer is so successful.