Livestrong.com speaks to experts including Marci A. Goolsby, MD, sports medicine physician and medical director of the Women Sports Medicine Center (WSMC) at HSS on developing relative energy deficiency in sport (RED-S).

Say you recently started — or ramped up — your fitness routine, with a specific goal in mind. But as the days and weeks pass, you're feeling cranky, foggy and tired. It might seem like the harder you work at the gym or on the running or cycling path, the less progress you make.

What's behind this frustrating situation? You may have created a mismatch between the amount of calories or energy you take in and how much you're expending.

If these symptoms are seeming familiar, talk to a health care provider trained in sports medicine. With their help, you can identify gaps in your nutrition, whether that's skipping meals or not getting enough carbs, protein or fats, and work to fill them.

"Your body is like a race car; it needs enough fuel and the right kind of fuels to keep the machine going at top performance," Dr. Goolsby said.

You might also discuss changes to your fitness regimen: dialing down the intensity or increasing the amount of rest you take between workouts, for instance. If you struggle to make changes or have other signs of disordered eating or exercise addiction, a sport psychologist or eating disorder specialist can also play a key role in treatment, Dr. Goolsby advised. 

Read the full article at livestrong.com.