These studies are about young female cross-country skiers. But they highlight a trend I’ve noticed coaching women over 40 who are into running and other recreational endurance activities:

Not eating enough calories to support their activities. Especially around training time.

This can hurt your performance and recovery. And when you’re not getting enough food when you need it, it’s easier to make poorer food choices later on.

“Young female cross-country skiers had similar EA (energy availability) and CHO intake over four training periods. Both EA and CHO intake were at suboptimal levels for performance and recovery.” Here’s the study. 

This second study highlights one potential solution to eating enough for your goals—having adequate nutrition knowledge.

“In conclusion, young female cross-county skiers had difficulties meeting recommendations for optimal EA and carbohydrate intake. Better nutrition knowledge may help young athletes to meet these recommendations.” Here’s the second study.