Been there.
How bad can it get? erm, I was unable to tolerate light for a week, could barely get from bed to toilet without help.
I went on a very very restrictive diet for some time. 12 years later my diet is still wheat-free.
Your friend is taking a diet very high in sugar and nothing else, which will really throw out her digestion.
My 'recovery' diet was potato (no skins) and yogurt (live plain yogurt only) for 2 weeks, then gradually introducing vegetables, steamed or boiled only (no dairy other than the yogurt). Definitely no alcohol.
Once my strength came back I had tests. It was very very clear that I could no longer tolerate wheat. Initially I couldn't take oats, rye, barley either. Eating so much as a small bite of bread or half a biscuit produced agonizing stomach cramps within a couple of hours.
I guess she is already seeing a gastroenterologist.
From my experience:
Eat very small quantities of carbohydrate. Chew very very thoroughly. A good treat is to slice a baked potato, then grill (no fat) the slices. Add a bit of salt.
Keep down the sugar intake.
Fennel, the herb, has a marvelous calming effect. Just chew the herb, you don't have to swallow it.
Plain boiled brown rice, with a bit of salt or seasoning like Herbamare is good. Plain food is better.
