GLOSSARY

Energy Availability Calculation Table

EA is a research and assessment construct with substantial measurement uncertainty; no single threshold diagnoses REDs in every athlete.

Energy Availability Calculation subtracts exercise expenditure from energy intake and divides the result by fat-free mass over the specified period. Input error can substantially change the estimate.

Energy availability describes dietary energy remaining after exercise expenditure, expressed relative to fat-free mass over a defined period. It differs from whole-day energy balance and from body-fat percentage. Calculations are sensitive to errors in food records, exercise expenditure and body-composition estimates. No single threshold or short observation establishes a diagnosis for every athlete. Persistent fatigue, impaired recovery or other concerning changes warrant assessment in the broader health and training context rather than a conclusion from one calculated value.

Energy requirements depend on body size and composition, activity, life stage and physiological circumstances. A maintenance estimate is a starting point for a defined situation rather than a permanent personal calorie ceiling. Training load, recovery, appetite and changes in body mass help evaluate its usefulness. Growth, illness or a change in training schedule may require reassessment. Adequate energy also needs appropriate carbohydrate, protein, fat and micronutrient provision; matching a calorie total alone does not guarantee a balanced sports diet.

For example, stable body weight during a heavy training block does not establish adequate energy availability. The athlete may have compensated elsewhere while recovery deteriorates. Review intake, exercise load, symptoms and the quality of the estimates together, with appropriate assessment when concerns persist, rather than relying on a single calculated threshold.