GLOSSARY

Fasting-to-Fed Transition readjusts pathways when nutrients become available again.

Meals change uptake, storage, use and hormones; postabsorptive periods increase reliance on stores and endogenous supply. The transition is not an exact clock switch identical for every meal. Mixed foods and recent exercise alter patterns. Athletes should consider session goals, total daily adequacy and tolerance rather than assuming fasted or fed conditions are superior for every outcome. An acute metabolic shift does not directly establish long-term body composition or training benefit.

Overnight fasting differs from prolonged severe starvation. As restriction continues, glycogen, gluconeogenesis, fat and ketone contributions shift without eliminating all glucose and protein needs. Survival adaptation is not automatically optimal sports preparation. Severe prolonged undernutrition can also require supervised nutritional restoration, unlike ordinary pre- and post-exercise meal planning. Interpret duration and energy context rather than treating every fast as the same metabolic condition or a guaranteed route to better performance.