In 2014, the International Olympic Committee named a syndrome affecting many of its athletes: relative energy deficiency in sport, or REDs. It's now estimated that more than 40% of professional athletes have REDs, and the rate could be even higher in recreational athletes and exercisers. Athletes develop REDs when they consistently expend more energy through their physical activity than they take in through their diet. Over time, this prolonged energy deficit can lead to a wide range of symptoms, including hormonal and reproductive issues, insomnia and fatigue, bone weakness and injury, and a higher risk of anxiety and depression. Now,...