What Happens If You Keep a Fast for All 9 Days Without Break

In the Vedas, and later in the epics and Puranas, vows and fasts are ways of ordering the self, controlling senses, cultivating purity and devotion. The Sanskrit word vrata means vow or resolve, often involving self-restraint, especially in food, behavior, speech. The Bhagavad Gita frequently speaks of tapasya (ascetic effort, austerity) as essential for spiritual advancement, including control over senses, moderation in eating, and sacrifice. Fasting is one form of this.

In the spiritual literature, continuous austerity has both promise and warning.

• Heightened consciousness, discipline: Fasting helps still the cravings, the senses; helps mind focus and heart detach. The mind begins to see beyond the habitual.
• Purification: Not just of the body, but deeper layers: regrets, attachments, ego.
• Devotion and surrender: When there is hunger, discomfort, one tends to lean more on prayer, on inner strength, on remembering the Divine, rather than on self-will.

• Pride, false asceticism: If fasting is done for show, or to show one is more “spiritual” than others, it loses its purity. The scriptures caution against austerity performed with vanity, or with motives that are not aligned with dharma.
• Loss of clarity: After some days, when physical distress grows, the mind may wander, become clouded. One might misinterpret experiences or feel spiritual exaltation that's actually psychosomatic or mental illusion.
• Neglect of one’s duties: If the fast impairs one’s ability to care for family, do one’s work, maintain relationships, then the fast’s purpose is compromised.

The Gita gives a key warning: in Chapter 6, verse 16, Krishna tells Arjuna that yoga is not achieved by eating too much or too little, nor by sleeping too much or waking too much. There must be moderation. So extreme fasting that pushes the body and mind into distress may be contrary to that teaching.
Also, scriptures emphasize shraddha (faith, sincerity) and dharma (righteousness) in how one observes a vrata. It's not only the external act, but how one holds the heart. The quality of intention matters.

Nine days is a special number in Hindu devotional practices: e.g. Navaratri (nine nights) devoted to the Goddess; sometimes fasts of nine days are observed for special vow. It carries symbolism: the soul purifying through phases; nine is three threes, etc.
If one goes all nine days without break, the person is pushing it beyond common ritual fasting. But if done wisely, with partial fasts (e.g. taking water, or light food), with rest, with devotional support, with meditation, etc., the nine days can be deeply transformative.

Drawing from scripture and contemplation, here is what someone might learn (or be changed in):

• Simplicity is deeper than accumulation: When the body is freed from constant feeding, one sees how much of life is built around satisfying sense-desire. One starts appreciating what one already has more fully.
• Time inside pain reveals truth: Discomfort, hunger, fatigue force the mind inward. With that, one may see patterns: where one’s attachments lie; how weak one’s will is; how often one uses pleasure to avoid truth.
• Dependence & humility: Fasting reminds that we are fragile; that we depend on providence; that sense of gratitude grows: for water, for food, for rest, for breath.
• Faith tested becomes faith strengthened: If someone fasts nine days, there will be moments when faith wavers, or when doubts arise. Enduring these, holding steady in devotion, can build inner strength in a way shorter fasts do not.
• Balance matters: The fast shows that austerity must be balanced with care. Austerity for its own sake, without kindness to one’s body, risks self-harm. Scriptures teach that dharma includes caring for one’s own health.