OK, none of us (that I know of) lives in a stereotypical shtetl, the small, insulated Jewish neighborhoods of Eastern Europe. Not all of us are Jewish, and not all of us can fast -- Yom Kippur, Ramadan, Good Friday, or other religious reasons notwithstanding.
Religious fasting has a couple of different stated purposes, including celebration, mourning, sacrifice, intense introspection, and attempts to "reach a higher plane of consciousness" or to "come closer to [the Deity]". The intended results of the fast may be a feeling of privation or a feeling of exultation, and a focus on improving the spiritual self. In any case, approaching the fast without preparation can make it much more difficult to endure, both in terms of subjective feeling and objective physical health.
In modern times, there has been a lot of discussion about whether or not people with diabetes are obligated to observe religious fasts, forbidden from fasting, or something in between. Both Jewish and Muslim teachings tell us that we may not fast if that fasting endangers our lives (or if we are pregnant or nursing, the lives of our babies), but there is a broad range of interpretation of where the point of endangerment actually lies. As a result, you will find both secular and ultra-observant people with diabetes insisting they can and must fast, or insisting they may not fast, or that they may only engage in a "limited" fast (in which the hours of the fast are lessened, or lesser amounts of food and water are consumed). Our beliefs on this are fashioned by the traditions with which we grew up, our religious advisors, and (hopefully) our medical teams.
For those of us with diabetes who choose to fast for religious reasons, there are a number of resources available on the Internet to assist us. Jewish Friends With Diabetes gives us some guidance for dealing with diabetes during the 25- to 27-hour Yom Kippur fast, in which we neither eat nor drink. Articles in Tablet magazine and other Jewish media give general information on making fasting easier. Diabetes UK, Crescent Life, Diabetes Care, Children With Diabetes, and Teach Islam provide medical and/or religious guidance for managing diabetes with the repeated dawn-to-dusk fasting of Ramadan. This guidance includes how to prepare for the fast, when it should be broken regardless of religious restrictions (if one goes seriously hypo, for example), and exhortations to consult with one's private physician and one's personal religious advisor before fasting.
There are also a number of medical reasons for which one must undergo periods of fasting. These include our periodic blood diagnostics (mine are quarterly), diagnostic procedures such as CAT scans, ultrasound, or cardiac stress tests, surgical procedures, and the bane of all pumpers: basal testing.
In the "chicken or egg" scenario, if one is observant enough to fast for religious reasons, but not observant enough to refrain from writing or using the computer, one might be able to use the time of a religious fast to perform basal testing; on the other hand, it may be useful for those of us who do not normally fast (except for specific medical reasons) to look at some of the tips and tricks our religious communities use to help us through our fasts with minimal physical discomfort.
Whether or not you observe religious fasts, and how you observe them, is a personal matter between you, your family, your medical team, and your relationship to [the Deity]. If the wisdom of those who have walked these paths before us can make your medical fasts more endurable as well, then perhaps that is their unintentional contribution towards tikkun olam, improving the state of the world.
