Glucose conversion (how the body stores & makes sugar)
Blood glucose is kept in a tight range no matter whether you just ate or have been fasting all night. The body does this by converting glucose between three forms — burning it, storing it as glycogen, and manufacturing new glucose when supplies run low.
How it works
- Glycolysis — glucose is broken down for energy (feeds the glycolytic and, via pyruvate, the oxidative systems).
- Glycogenesis — after a meal (high insulin), spare glucose is chained together into glycogen in liver and muscle for later use.
- Glycogenolysis — between meals or during exercise (glucagon/adrenaline), glycogen is broken back down to glucose.
- Gluconeogenesis — in prolonged fasting the liver builds brand-new glucose from lactate, amino acids and glycerol to protect the brain.
Why it matters
Muscle glycogen fuels hard training; liver glycogen keeps blood sugar steady overnight. Depleting glycogen (long fasts, low-carb, endurance) shifts the body toward burning fat and, eventually, gluconeogenesis — relevant to fat-loss and metabolic-flexibility protocols.
Key hormones: Insulin (store: glycogenesis), Glucagon & adrenaline (release: glycogenolysis), Cortisol (gluconeogenesis)