Hunger is the adornment of the people of Allah (ahl Allāh). By this, I mean the habitualization of hunger. This is mevt-i ebyaz (white death).
In the path of Sufism (taṣawwuf), the hunger deemed appropriate for the righteous (ṣāliḥūn) is that which reduces the excesses of the (individual) nature and chooses to desire the world without the need to act for it. If the aspiration rises, it seeks the attribute of Samadiyya (Divine Self-Sufficiency). Its limit for us is a one-day fast. If sleeplessness is added to this, it becomes a legitimate and voluntary hunger. For us, this is only a way that can be considered legitimate. If Allah had not limited this state of necessity for the common people (ʿawām), their state would not be close to this level.
A person cannot know better than his Lord the benefits that come to the servant from increased hunger. Such a thought is the utmost point of bad etiquette. If, during the night (in worship) and in his annihilation (fanāʾ), he finds himself fed and given drink by another state, and if he finds its effect in his strength, the soundness of his intellect, and the preservation of his temperament, he attains what he desires. He is not fit for hunger.
Our discourse on hunger, even if it concerns the One who leads him to the state of absorption (istighrāq), is such that, like Abū Uqqāl, a strong influx (wārid) may come between him and hunger. If he derives benefit from this, this is what is intended and sought by the Sufis. If he does not benefit, this is an illness, and this state should be referred to a physician. This is not a state aimed at by the Sufis.
The hunger of the great ones, however, is compelled (iḍṭirārī) hunger. That which leads to hunger in them becomes a habit (malaka) that does not disappear in either hunger or satiety. He is content with little. However, they abstain from the lawful (ḥalāl) either for vigor in acts of obedience or to lighten the reckoning. (Futūḥāt, I, 184)
Mevt-i ebyaz is hunger. For hunger illuminates the interior of a person and brightens the face of the qalb (the heart). If the sālik (spiritual traveler) does not fill his stomach and continues to remain hungry, he dies with the white death, as opposed to mevt-i esved (black death).
It is then that he gives life to his intelligence. For gluttony kills intelligence. Whoever kills his gluttony, revives his intelligence. (Kāshānī, 92; Jāmiʿ, 100)