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.