Baha’u’llah’s advice for people who are “excused from fasting”

QUESTION: Concerning observance of the Fast by people engaged in hard labour during the month of fasting.

ANSWER: Such people are excused from fasting; however, in order to show respect to the law of God and for the exalted station of the Fast, it is most commendable and fitting to eat with frugality and in private. (Baha'u'llah, Questions and Answers, The Kitab-i-Aqdas)