As to your question
regarding the Fast: if there is any doubt in the mind of a person as to whether
it will really be bad for that person's health to keep it, the best doctor's
advice should be obtained. But generally speaking most people can keep it, anywhere
in the world, with no detriment to their health. It is very good for the health
and, once one forms the habit, each year it becomes easier to keep, unless one
is rundown. No one is obliged to keep it if it really harms them.
- Shoghi Effendi (From a
letter written on behalf of Shoghi Effendi to an individual believer, April 14,
1947; compilation: Lights of Guidance)