Day 1: Initial Alterations
Blood Glucose Decrease: Absent food intake, the body's primary energy source, glucose, starts dwindling, leading the liver to release stored glucose (glycogen) to uphold blood sugar levels.
Decline in Insulin Levels: As blood sugar levels dip, insulin secretion wanes, enabling the body to shift towards utilizing stored energy reservoirs.

Day 2-3: Commencement of Ketosis
Initiation of Ketosis: With glycogen reserves exhausted, the body commences the breakdown of fats into ketones for energy. This metabolic phase, termed ketosis, sees heightened ketone production.
Suppression of Appetite: The urge to eat diminishes as the body adjusts to utilizing ketones for fuel. Nevertheless, fatigue, lethargy, and cognitive haze may ensue during the adaptation phase.

What Happens To Your Body If You DON'T EAT For 5 Days?

Day 4: Enhanced Ketone Generation

Deeper Ketosis: Ketone synthesis amplifies, and the body enhances its efficiency in utilizing ketones for energy. Despite the diminishing hunger, heightened urine output may lead to dehydration and electrolyte imbalances.

Muscle Catabolism: In the absence of adequate protein intake, the body may initiate muscle tissue breakdown to procure amino acids essential for vital functions.

Day 5: Continued Adjustment
Heightened Exhaustion: Energy levels may further plummet as the body predominantly relies on fat reserves and ketones for sustenance. Physical and cognitive weariness may intensify.
Potential Health Hazards: Prolonged fasting can precipitate nutrient deficiencies, electrolyte imbalances, and muscle wasting. Individuals with underlying health conditions may encounter adverse effects like vertigo, fainting, and irregular heart rhythms.

Conclusion
While short-term fasting can potentially confer health benefits such as fostering cellular rejuvenation and metabolic adaptability, embarking on a five-day fast sans medical supervision harbors risks. Consulting a healthcare professional before undertaking prolonged fasting, particularly for individuals with medical ailments or those in pregnancy or lactation, is imperative. Sustaining adequate hydration, electrolyte equilibrium, and nutritional sustenance are paramount for mitigating potential health hazards during protracted fasting spells.