January 8

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 run down. No one is obliged to keep it if it really harms them. 
- Shoghi Effendi  (From a letter dated 14 April 1947, written on behalf of Shoghi Effendi to an individual believer; ‘Messages to Canada’)