The Claim
Fourteen days of low energy availability at 22 kcal/kg fat-free mass per day in female endurance athletes reduces 20-minute time trial performance by 7.8%, and this reduction persists after three days of energy repletion despite normalization of cortisol and inflammatory protein levels.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
Female endurance athletes who consume too few calories for 14 days perform 7.8% worse in a 20-minute time trial, and this performance drop does not reverse after three days of eating normally, even though cortisol and inflammatory markers return to normal levels.
See the scientific wording
Fourteen days of low energy availability (22 kcal/kg fat-free mass/day) in female endurance athletes reduces 20-minute time trial performance by 7.8% and this impairment persists after three days of refueling, despite restoration of cortisol and inflammatory proteins.
When energy intake is too low for too long, immune cells produce excessive reactive oxygen species that damage cellular components and disrupt energy use in muscles. Even after eating normally again, these immune cells remain overactive and keep producing too much oxidative stress, which interferes with how muscles generate force and sustain effort during intense exercise.
What the research says
1 studyWhen female runners don’t eat enough for two weeks, their body gets stressed and they get slower at running. Even after eating normally for three days, they still don’t get their speed back—just like the study found.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.