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Do you exercise a lot?
Being active is great. In fact, girls should be active at least an hour each day. Sometimes, though, a girl will be very active (such as running every day or playing a competitive sport), but not eat enough to fuel her activity. This can lead to health problems. Learn about how much food active girls need to eat and signs of not eating enough.
Read about what can happen when girls don't eat enough to fuel their activity:
These three sometimes are called the female athlete triad. ("Triad" means a group of three). They sometimes also are called Athletic Performance and Energy Deficit. (This means you have a "deficit," or lack, of the energy your body needs to stay healthy.) Keep reading to learn more.
A problem called "low energy availability" 
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Your body needs healthy food to fuel the things it does, like fight infections, heal wounds, and grow. If you exercise, your body needs extra food for your workout. You can learn how much food to eat based on your activity level using the MyPlate Checklist Calculator.
"Energy availability" means the fuel from food that is not burned up by exercise and so is available for growing, healing, and more. If you exercise a lot and don't get enough nutrition, you may have low energy availability. That means your body won't be as healthy and strong as it should be.
Some female athletes diet to lose weight. They may do this to qualify for their sport or because they think losing weight will help them perform better. But eating enough healthy food is key to having the strength you need to succeed. Also, your body needs good nutrition to make hormones that help with things like healthy periods and strong bones.
Sometimes, girls may exercise too much and eat too little because they have an eating disorder. Eating disorders are serious and can even lead to death, but they are treatable. Learn more about eating disorders.
Period (menstrual) problems top
If you are very active, or if you just recently started getting your period (menstruating), you may skip a few periods. But if you work out really hard and do not eat enough, you may skip a lot of periods (or not get your period to begin with) because your body can't make enough of the hormone estrogen.
You may think you wouldn't mind missing your period, but not getting your period should be taken seriously. Not having your period can mean your body is not building enough bone, and the teenage years are the main time for building strong bones.
If you have been getting your period regularly and then miss three periods in a row, see your doctor. Not having your period could be a sign of a serious health problem or of being pregnant. Also see your doctor if you are 15 years old and still have not gotten your period. Learn more about period problems.
Bone problems top
Being physically active helps build strong bones. But you can hurt your bones if you don't eat enough healthy food to fuel all your activity. That's because your body won't be able to make the hormones needed to build strong bones. Learn about how much food active girls need to eat.
One sign that your bones are weak is getting stress fractures, which are tiny cracks in bones. Some places you could get these cracks are your feet, legs, ribs, and spine.
Even if you don't have problems with your bones when you're young, not taking good care of them now can be a problem later in life. Your skeleton is almost completely formed by age 18, so it's important to build strong bones early in life. If you don't, then later on you could wind up with osteoporosis (say: OSS-tee-oh-puh-ROH-suhss), which is a disease that makes it easier for bones to break. Learn more about foods that help build strong bones.
Signs of not eating enough and eating disorders top
Sometimes, girls exercise a lot and do not eat enough because they want to lose weight. Sometimes, exercising just lowers a person's appetite. And sometimes limiting food can be a sign that a girl may be developing an eating disorder. Here are some signs that you or a friend may have a problem:
- Worrying about gaining weight if you don't exercise enough
- Trying harder to find time to exercise than to eat
- Chewing gum or drinking water to cope with hunger
- Often wanting to exercise rather than be with friends
- Exercising instead of doing homework or other responsibilities
- Getting very upset if you miss a workout, but not if you miss a meal
- Having people tell you they are worried you are losing too much weight
If you think you or a friend has a problem, talk to a parent, guardian, or trusted adult.
Sometimes girls exercise a lot because they feel pressure to look a certain way. Soccer star Brandi Chastain knows how bad that can feel. It took a while, she says, for her to realize that only she was in charge of how she felt about her body. "Body image is tough, but it is something we have to take charge of," Brandi says. "Because inside, only we know who we are." Watch a great video about how her teammates never judged each other based on appearances.
Content last reviewed March 27, 2015
Page last updated May 7, 2018
