Energy per kilogram in performance and elite sport

Three quantities with different meanings

Dietary intake per kilogram of body mass describes the size of an energy intake relative to the athlete. Total energy expenditure per kilogram describes expenditure. Sports energy availability subtracts exercise energy expenditure from intake and divides by fat-free mass (FFM). Identical units on a page do not make these interchangeable. The IOC discusses the limitations of treating 30 kcal/kg FFM/day as a universal threshold. [1]

Elite competition changes the scale

A 2024 case study of one Tour de France Femmes cyclist reported doubly labelled water expenditure of 7,572 kcal/day and food-photography intake of 5,246 kcal/day. It illustrates demanding competition, not a requirement for every athlete. [2]

Using the reported starting mass of 71.2 kg, those values correspond to approximately 106.3 kcal/kg/day expended and 73.7 consumed. These are calculations using baseline mass, not the study’s mean daily mass; intake covers race days 1–7. [2]

For a hypothetical 70 kg athlete, 25 kcal/kg body mass gives 1,750 kcal/day. If intake is 3,000 kcal/day, exercise costs 1,200 kcal/day and FFM is 55 kg, intake per body mass is 42.9 but energy availability is 32.7 kcal/kg FFM/day. These are worked calculations, not observations or recommended targets.

A performance study for EPK

EPK–009 proposes repeated measurement across rest, training and competition. It asks whether intake/body mass predicts subsequent performance and recovery after accounting for workload, body composition, carbohydrate availability and previous performance. A higher ratio alone is not evidence of a better diet.

This connects most directly to EPK–004 on functional capacity and EPK–005 on relative energy deficiency. EPK–003 supplies substrate-use questions; neither fat oxidation nor body-weight stability independently establishes adequate energy availability.

Related working papers

Read the relevant PDFs: EPK–001 to 007 are the revised version 1.2 papers; EPK–008 to 010 are version 1.0 supplements. Earlier PDFs and DOI records remain on the paper archive.