Contrary to what many women have been led to believe, the nutritional needs of female athletes are not significantly different from those of male athletes. Research has shown that male and female athletes and non-athletes need the same 13 vitamins and 22 minerals in approximately the same amounts. Most gender-based differences in recommended daily intakes of specific vitamins and minerals can be accounted for by differences in body size, such that they are really size-based differences. The lone exception is iron, which premenopausal women need more than twice as much of due to menstrual-related iron losses. Those vitamin and mineral supplements that are "formulated especially for women/men" are nothing more than marketing gimmicks.
The same is true for the macronutrients: carbohydrate, protein, and fat. Men and women need the same eight essential amino acids and the same essential fats. The optimal balance of macronutrients is also the same for male and female athletes: 40-70 percent carbohydrate, 15-40 percent fat, and 10-25 percent protein. The only diference is that the average man, being larger, needs more total calories each day than the average woman.
There are gender differences in the use of nutrients in the body. For example, women burn more fat and less carbohydrate than women at moderate exercise intensities, while men burn more fat and less carbohydrate than women in the first hour or two after exercise. But these differences do not suggest the need for the two genders to eat differently.
However, female athletes often do eat differently from male athletes in ways that prevent them from meeting some of their nutritional needs. For example, many women believe that females require more calcium than males. They do not. The reason some women believe their calcium needs are higher is that women are more likely than men to develop osteoporosis (dangerously low bone density), which is often caused in part by low bone density, and calcium is the main mineral ingredient of bone tissue. The problem of osteoporosis is so widespread that doctors and nutrition experts are constantly urging women to consume more calcium. But the calcium deficiency that sometimes contributes to osteoporosis is not due to higher calcium needs; rather, it is due to lower average calcium consumption in women.
A lot of women avoid calcium-rich dairy foods in an effort to avoid fat. This point leads us to the core nutritional challenge that female athletes (and women in general) face as a group: social pressure to be thin. As we all know, there is in our culture a double standard that makes fuller body shapes less acceptable in women than in men. This standard motivates millions of women - and girls - to undernourish themselves in a misguided effort to look the way they think they're supposed to look.
Athletes are as likely to be affected as non-athletes. In fact, compulsive exercise is another unhealthy way that some females attempt to achieve a warped ideal of thinness. While a great number of female athletes do develop serious eating disorders such as anorexia nervosa, much greater numbers undernourish themselves to a milder (but still unhealthy) degree. This broader phenomenon is often referred to as disordered eating. (Eating disorders are specific and severe forms of disordered eating.)
You may have heard of a condition called the female athlete triad. The three health conditions comprising this triad are disordered eating, amenorrhea (cessation of menses), and osteoporosis. Often, but not always, these conditions are present simultaneously in female athletes who are undernourishing their bodies due to negative body image. (Two-thirds of American women report being dissatisfied with their body weight).
Disordered eating is typically the trigger of the triad. Inadequate energy intake combined with intense training can cause a woman's body fat level to fall so low that the ovaries no longer produce adequate estrogen. This hormone is critical for normal menses and also for bone formation. Calcium deficiency, when combined with low estrogen, makes the bones even thinner and more brittle, thereby increasing the risk of stress fractures. Here are some tips to avoid undernourishing yourself as a female athlete:
Don't eat by your own rules. Eat by the established rules as explained in this book and other credible resources. And don't make up your own ideal body weight. Your ideal body weight is whatever body weight you end up with after consistently eating right and training well for several months. Focus on the process, not arbitrary goals that may or may not be realistic.
Ask yourself whether you are satisfied with your body weight. If you are not satisfied, and yet your body composition is in the healthy range, consider the possibility that the real problem is not your body weight but your body image, and talk to your doctor about it.
Beware of restricting certain types of foods. Many female athletes eliminate dairy from their diet or become vegetarians in order to facilitate weight loss. What they really end up doing is undernourishing themselves - eating too few calories, or not getting enough of specific nutrients that are most abundant in animal foods (e.g. protein, calcium, and iron). There is really no legitimate health reason to avoid dairy foods or meat. So unless you have an ethical or religious reason for doing so, I don't recommend it.
See a doctor if you miss three menses not due to pregnancy or if you suffer frequent stress fractures.