Are you doing this fast under medical supervision? 40 days of fasting is a Very long time.
I too have problems with bread and associated carbohydrates - not only do they give me fluid retention, internal disorders, and bad skin but one taste, one slice and I'm lost to the whole loaf; I find them very addictive.
I'm currently following a lower-carb diet (Dukan), which, hugely to my surprise, eliminated carb cravings from week one - but is giving me plenty of good food to eat and 13lbs lost in 4 weeks.
I don't have the medical knowledge to offer actual advice but as a fellow human being and body struggler, I would urge you to make sure your doctor is happy with your plans.
And I do indeed wish you luck!