Let's talk about Relative Energy Deficiency in Sport (REDs).
When an athlete is not meeting their energy needs whether intentionally or unintentionally, their body has to compensate to conserve energy. In a state of energy deficiency or where there is low energy availability, the body goes into survival mode to conserve energy. While an athlete may experience an initial increase in performance, ultimately their body cannot sustain being in a state of energy deficiency and performance declines.