By Trish Rooney The best advice for a successful workout? Eat. What was once deemed a woman’s problem, the “female athlete triad,” has a new name you should know: RED-S (relative energy deficiency in sport). Part of RED-S is consuming less calories than your body needs to function effectively, making everyday activities more difficult, including working out. Eating isn’t just fuel for workouts, it’s fuel for everything you do. Your brain, liver, and other organs all need calories to function properly, before you can focus on building muscle at the gym. In one study of male cyclists, the result…