This is an excerpt from Endurance Sports Nutrition-3rd Edition by Suzanne Girard Eberle.
Special Health Concerns for Vegetarians
A meatless diet does not guarantee good health and better performances. Unless you stick to some basic guidelines and stay up with your daily calorie and nutrient needs, you're likely to encounter some difficulties. Two particular problems that have been shown to slow vegetarian athletes are amenorrhea in females or a too-low testosterone level in males, as well as disordered eating habits.
Amenorrhea, Suppressed Testosterone, and Vegetarianism
Female athletes who adopt vegetarian diets may be at higher risk for amenorrhea, a serious medical condition characterized by low estrogen levels and the loss of menstrual periods. Male vegetarian athletes may be at risk for an abnormally low testosterone level. Women who follow a plant-based eating style typically have lower levels of hormones that affect menstruation, such as estrogen and prolactin, than do nonvegetarian women. Male athletes with diminished hormonal function are subject to the same fatigue, weight loss, frequent infections, increase in injuries, and diminished performances as their female counterparts. Early research on altered sex-hormone levels appeared to point to some component characteristic of a vegetarian diet as the cause; possibilities include high fiber intake, low fat or protein content, or the presence of weak plant hormones. More recently, however, studies point to an energy deficit or failure to consume enough total calories as the likely culprit.
Because amenorrhea, as well as suppressed testosterone levels in males, also are linked with extreme or extensive exercise, an altered hormonal status may be especially prevalent among vegetarian athletes. High rates of amenorrhea have been reported in vegetarian female athletes, particularly in runners. In one study, vegetarians made up 25 percent of the female runners with amenorrhea, but only 11 percent of the runners who had regular menstrual periods. In a study of eight male endurance athletes, following a lacto-ovo-vegetarian diet for 6 weeks led to a slight decrease in total testosterone levels.
If you develop amenorrhea (or fail to start your menstrual cycle by age 15) or your testosterone level is suppressed, don't ignore it. You're three times more likely to develop a stress fracture, and low levels of estrogen in females and testosterone in males at any age lead to premature bone loss. Examine your current eating habits. Often, gaining (you're actually restoring if you've lost weight) as little as 2 percent of body weight (2 pounds for a 120-pound woman and 3 pounds for a 160-pound man, or 1 kilogram for a 54.5-kilogram woman and 1.4 kilograms for a 73-kilogram man) and maintaining this healthier weight as you train is all that is needed for restarting menstrual periods or boosting a low testosterone level.
As an endurance athlete, you can easily burn off large amounts of calories exercising, so as indicated earlier, amenorrhea or a too-low testosterone level most likely results because of an energy imbalance. You simply aren't consuming enough calories daily to sustain your high energy expenditures. If your current vegetarian eating style doesn't keep up with your calorie needs, you'll need to eat more energy-dense foods and adequate fat (at least 20 percent or one-fifth of total calories) and protein, as well as cut back on fiber-rich foods that fill you up too quickly. Be prepared to initially cut back on how intensely you exercise, too, and to reduce your weekly training volume by 10 to 20 percent (possibly even more if you're a woman trying to conceive).
Along with eating a wide variety of plant proteins daily, be certain that you consume adequate high-quality protein, such as that provided by soybeans, milk, and egg whites. Other vegetarian foods lack one or more of the essential amino acids the body needs for efficient tissue growth and repair. The research suggests that athletes with amenorrhea, for example, tend to have diets low in protein compared with athletes who menstruate regularly. Some studies show that adding meat (red meat in particular) has a protective effect on menstrual periods, although it's unclear why. A similar scenario appears true for male athletes. A study that compared strength and muscle gains in men doing resistance training who were eating either a vegetarian diet or an omnivore diet, for example, found that meat eaters lost 6 percent fat mass and gained 4 percent muscle mass compared to the vegetarians.
Obviously, whether you include or exclude meat in your daily diet is a matter of personal choice. Depending on your individual needs and your long-term goals, however, you may want to reevaluate the effect that including small portions of meat several times a week could have on your health and performance.
Disordered Eating and Vegetarianism
Some vegetarian athletes, male and female, inadvertently consume too few calories to sustain their high energy output. Others, however, consciously restrict the foods that they eat under the guise of vegetarianism. In other words, they choose (or choose to continue) a vegetarian eating style as a way to control their weight and cope with pressure to be thin. These athletes may feel better about themselves or superior to others when they eat differently, or they may feel more perfect if they don't eat certain foods.
Some hallmark behaviors to look for are vegetarians who narrow their protein choices to a few items they feel are acceptable; avoid fat by shunning nuts and seeds, nut butters, dairy products, and other higher-fat items; and skip meals or elect not to eat in social settings rather than prepare or search out vegetarian fare. If you, or someone you train with or coach, pursue vegetarianism primarily as a politically correct means to lose weight or to achieve a lean appearance, heed the warning signs. Such harmful and ineffective eating behaviors set you up for anemia, stress fractures, and possibly a full-blown eating disorder.
Parents and coaches of teenage athletes need to be especially vigilant when it comes to young people and vegetarianism. Evaluate the reasons that teens give for renouncing foods and the effectiveness with which they replace those foods with healthy substitutes. Girls, in particular, may adopt vegetarianism as a socially acceptable way to mask their disordered eating habits.
Researchers at the University of Minnesota surveyed high school students across Minnesota and found that teenage vegetarian girls are twice as likely to diet, four times as likely to induce vomiting, and eight times as likely to use laxatives as are their meat-eating peers. These findings support a reverse study of 116 patients who suffered with anorexia nervosa (self-induced starvation): 54 percent avoided red meat, although only 4 percent had done so before the onset of their eating disorder.
One of my clients, a 13-year-old who adopted a vegetarian diet at age 5, played soccer, swam, ran, and participated in gymnastics during a typical week. When a swim coach at a summer camp delivered the erroneous message that athletes should avoid eating fat, my client began to count calories and fat grams, skip meals (saying that she was not hungry or that the vegetables tasted terrible), and exercise twice a day. After she lost 10 pounds (4.5 kg) and her menstrual periods stopped, her parents took action.
When I met her, I found that besides not eating meat, she didn't like fish, rarely drank milk, ate eggs only if they were prepared for her, and wrinkled her nose at the mention of beans or tofu. Obviously, with this approach, she wasn't meeting her everyday protein, iron, and calcium needs. She also wasn't consuming enough food (calories) to match the calories that she expended daily through exercise. Fortunately, a strong desire to continue her sports activities motivated this teen to restore the lost weight. She ate more of the foods that she liked, and after a few months, she began to eat some foods that she had previously considered forbidden.
A vegetarian diet can be either a healthy way to eat or a haphazard eating style that comes up short in many key nutrients. To reap the benefits of vegetarianism, you must be willing to do two things: stock your kitchen with some vegetarian staples (and know how to prepare them!) and invest some time and energy exploring new foods that will help you meet your nutrition needs.
Quick and Healthy Vegetarian Snacks and Meals
Items to prepare
Whole-grain muffins or cookies
Graham crackers, rice cakes, whole-grain crackers, tortillas
Instant macaroni and cheese, couscous with lentils, polenta, or mashed potatoes
Instant brown rice or other whole grains
Bagels or whole-grain bread with nut butter
Oatmeal or cold cereal with milk
Dried fruit—raisins, apricots, dates, figs, papayas, apples
Frozen juice bar
Bean taco, burrito, or enchilada
Lentil or split-pea soup
Fruit shakes or smoothies
Low-fat cottage cheese, low-fat cheese (dairy or soy)
Yogurt (dairy or soy)
Canned beans, vegetarian chili
Ethnic frozen meals—Mexican, Chinese, Thai, or others
Tofu hot dogs
Quick mixes of tabbouleh, hummus, refried beans, or black beans
Roasted soy nuts or other nuts
Items to take when traveling
(Request hot water at mealtimes or prepare dehydrated items in room by adding hot water.)
Hemp or brown rice protein powder
Protein-rich energy bars
Freeze-dried or dehydrated tofu, dehydrated hummus, and instant lentil, split-pea, or other dried-bean soup mixes
Concentrated liquid calories in the form of protein-based beverages
(e.g., Power Dream soy energy drink, Boost, Ensure, Carnation Instant Breakfast drink/mix)
Learn more about Endurance Sports Nutrition, Third Edition.