GLOSSARY

Fed vs Fasted Exercise compares exercise after feeding with exercise after a specified fast. Define both conditions and distinguish acute fuel use from long-term performance or composition outcomes.

Training with reduced carbohydrate availability is a specific strategy rather than a synonym for all fasted exercise. Low muscle glycogen, reduced liver glycogen and withholding carbohydrate during a session are different manipulations. Some can alter molecular signaling, but a larger signaling response does not guarantee superior long-term performance. Reduced session quality and inadequate energy supply are relevant tradeoffs. Important high-intensity work and competition often require sufficient carbohydrate, and chronic underfueling should not be presented as a necessary adaptation method.

Periodization adjusts nutrition across sessions, days or training phases to support the work and its goals. Carbohydrate can be concentrated around demanding or important sessions while the broader diet still meets energy and nutrient needs. A lower-demand day can also be a recovery or preparation day, so rest does not imply that food or carbohydrate should be removed. Describe what changes, when and why, and evaluate the quality of subsequent training rather than treating variation itself as beneficial.

Muscle and liver glycogen have related but different roles. Muscle glycogen supplies the muscle in which it is stored, while liver glycogen helps support blood glucose. An overnight fast can reduce liver carbohydrate availability without producing the same depletion in every muscle. Starting concentration, recruited fibers and exercise demand affect use. An estimate of total stores does not directly describe the availability of every local glycogen pool during a specific movement.