Fasting in times of crises

[robrecht]

Don't take my word for it; I have no expertise whatsoever in Talmud. But I did read in the Talmud once that a sick person may be allowed to eat even unclean foods, even during the fast on Yom Kippur, if he is sickly from great hunger (Yoma 83a). I think this is based on a standard principle (פיקוח נפש piqquach nephesh, saving a life) such that one is also permitted to violate the Sabbath to save life or care for the sick (Yoma 84b-85a).

Please correct me if I'm wrong.