Wiktionary
a. Not nourishing.
Usage examples of "unnourishing".
From this very moment onward, the bodies of those most steeped in evil will reject this food and any other taken from the Mother, retaining only unnourishing water, so that day by day will the evilest ones of you weaken and sicken as their evil-steeped husks waste away and at last die, that their spirits may return to the Mother and be once more cleansed in the Sacred, Healing Fires.
To dine upon the taste and goodness of victuals, without eating the unnourishing substance?
This, however, it was easy for him to assuage, after a fashion, for the long, gray, unnourishing mosses were abundant.
She did not even know that she drank life from Du, although it became obvious, after long questioning, that she had eaten nothing more than some rather tasteless and relatively unnourishing moss for many days.