3.1 Human Metabolic Flexibility

Humans can use both glucose and fatty acids as energy substrates under different scheduling states.

Human FBM uses the fatty-acid side of this flexibility to establish a long-term low-occupancy pattern.

Exogenous carbohydrate load determines whether repeated glucose scheduling remains dominant.

Insulin occupancy determines transition access toward fatty-acid direct energy.

Energy sufficiency and lean-mass stability determine post-transition sustainability.

When input architecture changes, occupancy trend changes, and substrate priority changes accordingly.

With reduced occupancy plus sufficient energy, fatty acids can carry dominant direct energy duty.

After stable transition, meal-to-meal energy continuity increases and hunger variance decreases.

Daily execution tends to align with more predictable satiety rhythm.

Human flexibility constraints differ from obligate-carnivore constraints in feline systems.

This page describes transition conditions, not cross-species parameter equivalence.