Also, you might want to check out the "Ask the Experts" link here on MedHelp and chieck out some of the experts' profiles & interests. Some physicians/endocrinologists, dieticians and other health care professionals there have a particular interest and expertise in the area of diabetes care and would be best qualified to answer your question or direct to sources of additional information.
Here's a link you may find helpful/interesting:
There are a lot of reasons why people choose to fast. Some hope to lose weight, some hope to cure illness, some hope to achieve greater mental clarity or physical comfort/function, and many do it as a spiritual practice. What is your reason for wanting to fast, cat139?
The school of thought that fasting may help cure illness is not new. It's been around since ancient times when some cultures believed they could cure diseases---for example syphyllis (clearly a false belief)---through fasting. More recently a wide variety of "healers" (some educated & qualified, many not) have claimed that fasting can cure many ailments, including diabetes. Long-term fasting in anyone has potential dangers and should not be undertaken without close monitoring by a physician, nurse practitioner, medical dietician (as part of a multi-disciplinary team) or other qualified health care provider. Those with serious or chronic illness may develop ill effects even from short-term fasting and should be especially vigilant in seeking medical monitoring; this is especially true of diabetics who could have serious and even life-threatening drops in blood sugar if they do not eat regularly. Most health care professionals don't believe that diabetes can be "CURED" though they recognize that it can often be CONTROLLED using weight control, exercise, life-style and dietary interventions. While there have been a handful of studies that have suggested (but not proven) that insulin function in the diabetic may improve after fasting, it has been unclear whether this benefit resulted directly from the fasting, due to weight loss or from some combination of factors. There have been few (if any) large, well designed studies that prove the efficiency or safety of fasting in diabetics.
If one wishes to fast as a way to lose weight, it is usually NOT a good idea or effective method. When deprived of food, the body goes into starvation mode, slows the metabolism and clings to every calorie, just as Bran explained (good job, Bran). Lean muscle can be cannibalized as a source of energy and the loss of muscle reduces calorie burn. And, in diabetics, again, fasting can result in dangerous drops in blood sugar levels.
Most religions that prescribe fasting as a spiritual requirement or exercise make exceptions for diabetics or those who are aged or ill. They may excuse the person from the fast entirely or modify it so that it is less restrictive. If a person with diabetes wishes to fast for religious reasons, they should seek guidance from their spiritual leader and advice/supervision from their physician/nurse practioner/health care provider.
In any case, whatever the reason for wishing to fast, noone can answer the question about how long a diabetic can safely fast because each diabetic is an individual and many variables could change the answer. Some of these variables include: is the fast a total one or partial? how much insulin, if any, does the person's body produce and how effectively does it function? is the patient on any medications that could provoke a hypoglycemic reaction in the absence (or shortfall) of food? do they have other illnesses that have to be taken into consideration? what is their weight and activity level? With all of these variables---and many others---only a healthcare provider who knows you well and examines you personally could even approximate an answer.
I'm not sure exactly but I dint know darling that fasting gets you no were it actualy puts you behind. Because when you fast your matabalizm slows down there for you gain weight in the long run. You can't not eat forever so when you start eating again if you fast you'll just gain weight. That's what stoped me from fasting. I fasted for 2 days. Well not exactly I ate dinner because my mum made me but I ate as little as possible.
Hoping you get better