🍽 Intermittent Fasting Metabolic Switch Simulator

Fed State: Running on Glucose

Right after eating, the body burns glucose first and stores the rest.

• Glucose: Primary fuel (placeholder metric)
• Full: Liver glycogen (placeholder metric)
• High: Insulin level (placeholder metric)
• Trace: Ketones (placeholder metric)

Fed-state fuel handling

Placeholder: dietary glucose is oxidized and stored as glycogen.

Fasting Drains Liver Glycogen

Without new glucose, the liver empties its glycogen reserve over hours.

• ~10-12h: Glycogen half-life (placeholder metric)
• Stable: Blood glucose (placeholder metric)
• Rising: Fat mobilization (placeholder metric)
• Low: Ketones (placeholder metric)

Depletion dynamics

Placeholder: glycogenolysis maintains glucose until stores run low.

The Metabolic Switch to Ketosis

As glycogen runs out, the liver shifts to producing ketone bodies.

• ~12-16h: Switch onset (placeholder metric)
• Fatty acids: Ketone source (placeholder metric)
• Partial: Brain fuel shift (placeholder metric)
• Rising: Ketones (placeholder metric)

Ketogenesis mechanism

Placeholder: hepatic beta-oxidation yields ketone bodies for fuel.

Cellular Stress-Resistance Pathways

Ketosis and fasting cues switch on autophagy and repair pathways.

• Elevated: Autophagy (placeholder metric)
• Increased: BDNF signaling (placeholder metric)
• Reduced: Oxidative stress (placeholder metric)
• Lower: Inflammation (placeholder metric)

Resilience pathway activation

Placeholder: ketone signaling upregulates protective cellular pathways.

Switch Timing Differs Between People

Metabolic health, muscle mass, and habits shift when the switch occurs.

• Faster switch: Lean, active (placeholder metric)
• Slower switch: Metabolic syndrome (placeholder metric)
• Faster switch: Habitual fasters (placeholder metric)
• 12-36h: Typical range (placeholder metric)

Sources of variability

Placeholder: genetics, liver glycogen capacity, and activity shift timing.