In the case of fast-days the conspicuous abstention from gainful occupations and from all pursuits that (materially) further human life is further accentuated by compulsory abstinence from such consumption as would conduce to the comfort or the fullness of life of the consumer.
It may be remarked, parenthetically, that secular holidays are of the same origin, by slightly remoter derivation.

They shade off by degrees from the genuinely sacred days, through an intermediate class of semi-sacred birthdays of kings and great men who have been in some measure canonized, to the deliberately invented holiday set apart to further the good repute of some notable event or some striking fact, to which it is intended to do honor, or the good fame of which is felt to be in need of repair.

The remoter refinement in the employment of vicarious leisure as a means of augmenting the good repute of a phenomenon or datum is seen at its best in its very latest application.
A day of vicarious leisure has in some communities been set apart as Labor Day.

This observance is designed to augment the prestige of the fact of labor, by the archaic, predatory method of a compulsory abstention from useful effort.

To this datum of labor-in-general is imputed the good repute attributable to the pecuniary strength put in evidence by abstaining from labor.