Energy balance in highly trained female endurance runners

Anecdotal and scientific reports have suggested that some female endurance athletes may have an inexplicable imbalance between energy intake and energy expenditure. We compared energy intake (EI) from food diaries (FD) with assessment of free-living energy expenditure (EE) using doubly labeled water (DLW) and a food attitude survey for 7 d in nine female distance runners. Daily EE via DLW (2990 ± 415 kcal) was greater (P< 0.01) than daily EI via FD (2037 ± 298 kcal): a 32% imbalance. Body weight did not change during the 7 d (day 1, 55.3 ± 6.2 kg; day 7, 55.1 ± 5.6 kg). A positive relationship was observed between EE and body weight (r = 0.82) while a negative correlation existed between EE vs EI (r = -0.83) and between EI vs body weight (r = -0.74). A negative correlation was observed between body weight and food attitude/body image (r = -78), i.e., the heavier women self-reported lower EI and also reported lower body image scores. These female athletes had a significant imbalance between EI and EE by our measures. Since body image and EI were related to body weight, the estimates of EI may be low due to underreporting particularly by the heavier athletes.