Each year since the passage of Title IX, greater numbers of women from all age groups have been competing in endurance sports. Like their male competitors, they share many of the same nutrition-based concerns: maintaining energy, optimizing body composition, and improving performance.
Although their goals may be similar, there’s one important fact women must remember when it comes to nutrition: Women are not just small men. As a sports nutritionist, I often think female athletes overlook that fact. Nutrition issues are never just about physiology. Cultural roles, careers, children, spouses, economics, physiology, and psychology all factor into the food choices and nutritional needs for females. When planning a nutrition strategy for optimal sports performance, all of these variables need to be considered.
So what are the real nutrition differences between men and women? Do women primarily use carbohydrates for energy, or should their diet include more fat? What nutrients do women need more of? How does our culture affect nutrition habits and weight goals?
Cultural Influences on Female Nutrition Choices
Body-image issues are a common concern for female athletes. Issues often start in high school or college and continue into adulthood. Daily workouts, weekly races, and pressure to maintain a lean physique can be overwhelming when the stress of academics and social popularity are added to the mix. Even very successful female athletes can become obsessed with our culture’s emphasis on thinness. During the summer of 2003, Canadian World Championship silver medalist Sara Renner graciously shared with XC Ski World (www.xcskiworld.com) her speech given to a group of young Canadian women titled “How to Be Healthy and Happy Living in the Skin You’re In.” In the following excerpts, Ms. Renner offers advice drawn from her own struggles with nutrition and performance as a world-class cross country ski racer.
- Take personal responsibility for how we feel about ourselves.
- The most important person that you need to like you, is you!
- Believe and accept yourself. No one can do that for you.
- Most women struggle with their body image and the society pressure regardless of their physique.
- We can choose to feel that pressure or not.
Specifically addressing diet, she had this to say:
- Good eating habits are one piece in the puzzle to overall good health.
- “Are you on a special diet?” is the most common question I get asked.
- I am not on a diet.
- I eat what my body needs.
- Eat to be strong, not to be thin.
- Being thin is not the same as being strong.
- To be healthy is to be fast.
Maintaining Energy Balance: Benefits and Costs
In his book Racing Weight, Matt Fitzgerald states that “a runner weighing 160 pounds has to muster about 6.5 percent more energy to run the same pace as a runner weighing 150 pounds.” However, reaching and maintaining a very low body weight can have some negatives.
One of my clients is a 42-year-old triathlete. She complained: “I feel chronically fatigued, and I’m still over what I consider my best weight for competition.” A health-conscious athlete, she had eliminated foods recommended by popular diets in an effort to feel better and lose weight. Her diet contained no dairy products “because I heard they were bad for you,” and very little meat or fish. Her work and training schedules were very tight, and it was necessary for her to eat two meals and recovery snacks away from home. Although she faithfully used sports drinks and gels to provide energy during workouts, her recovery diet was low in protein and contained little fat. Most of her calorie intake was in the evening hours, past the ideal window for recovery when muscles are primed to replace energy stores. She had deficiencies in key nutrients (such as protein, fat, vitamin D, calcium, zinc, and iron) despite regular consumption of fruits and vegetables.
When a trained female athlete fails to recover from workouts lasting over two hours, it may be due to depleted intramuscular fat stores. Research has shown that during moderate-intensity exercise, intramuscular stores (fat stored within a muscle) can contribute as much as 20 to 30 percent of energy expended. In trials where female athletes performed a two-hour run at a moderately hard pace (67 percent of maximal oxygen uptake), intramuscular fat stores were not back to baseline even 70 hours later when the recovery diet was very low in fat (10-percent energy). In comparison, consumption of a moderate fat diet (35 percent of calories) restored intramuscular fat to baseline levels by 22 hours after the two-hour run. Both recovery diets in this trial were the same calorie level.
Chronic deficits in calorie intake may or may not cause weight loss; however, loss of menses or irregular menses are an indication of insufficient calorie intake to support reproductive metabolism. Loss of menses, once believed to occur because of the physiologic stress of exercise, is now known to be caused primarily by an inadequate calorie intake resulting in low estrogen levels. A powerful hormone, estrogen affects many aspects of metabolism — including bone health. One study of collegiate female runners found that 28 percent were suffering from menstrual cycle disturbances. The study also showed low bone mineral densities despite regular weight-bearing activity. A diagnosis of osteopenia (reduced bone mineral density) or osteoporosis (low bone mineral density) increases the risk of fractures by two to three times. Dietary recommendations to consume adequate calcium and vitamin D will be insufficient to restore bone health unless there is sufficient calorie intake to support energy demands, and estrogen levels are normalized.
Superfoods for Female Athletes
A healthy diet that supports exercise training must take into account individual food preferences, genetic and medical limitations such as lactose intolerance or celiac disease, and convenience. Despite the best intentions, many women find themselves at the window of a fast food restaurant or eating what the kids want — not necessarily what they need.
Here’s a simple approach to a healthy training diet: Try to include at least some protein and carbohydrates at each meal or snack. For example, instead of only eating a piece of fruit for a snack, include a piece of string cheese or a small Greek yogurt. Avoid foods with added sugars; use natural fruit instead. Portable, dairy-free protein sources include hard-boiled high-omega-3 eggs, seasoned tofu, soy milk, and nuts. Whole grain low-fat crackers, gluten-free crackers, and mini boxes of cereal are quick carbohydrate choices nicely complemented by milk, cheese, nut butters, or soy products.
The challenges of eating a healthy diet to support exercise training are greater for women who follow diet patterns that don’t include meat, fish, dairy products, grains, or processed foods. In order to avoid loss of muscle and bone or extreme fatigue, it may be advisable to consult with a certified sports nutritionist or sports medicine physician.
About the Author
Donna Marlor, MA, RD, CSSD
Donna Marlor is a registered dietitian (RD) specializing in nutrition for endurance exercise and weight management. She offers motivational coaching and behavioral skills training to change eating patterns. Donna has a successful private practice as a consultant to the U.S. Olympic Education Center in Marquette, MI, and works with many individual athletes from novice to elite. A former collegiate alpine and cross country racer, Donna has a personal interest in sports. She enjoys master’s level competition in cross country skiing and running, as well as spending time with her family and chocolate lab on many outdoor adventures in Upper Michigan. Donna can be reached at www.DonnaMarlor.com or (906) 360-9049.