The Athlete's Diet
A balanced diet provides all the necessary nutrients and calories the body needs to function properly. Those nutrients are carbohydrates, protein, fat, vitamins, minerals, and water. Athletes often want to know exactly what constitutes a "balanced diet." Just as there are many racing strategies that can achieve victory, there are a number of dietary patterns that provide good nutrition.

The U.S. government's Dietary Guidelines for Americans are national guidelines for healthy eating. Most nutritionists agree that dietary principles promoting good health in the general populace provide the foundation of a good diet for athletes. Those dietary guidelines recommend the following be eaten each day:

Important. The daily total of meat should be about 6 ounces. (This is roughly the size of a deck of playing cards.) You can occasionally substitute cooked dry beans and peas for meat.

As a minimum, athletes should eat the lesser number of daily servings suggested from each food group. Because of their larger body size and/or higher level of training, some athletes may need more than the larger number of recommended servings.

CALORIE REQUIREMENTS FOR ATHLETES
Calorie requirements vary greatly from person to person and are greatly affected by the level of physical activity, body size, age, and climate. Therefore, it is almost impossible to prescribe a universal daily caloric requirement for athletes. Ideally, calorie consumption should balance energy expended. If calorie consumption is consistently above or below an athlete's individual energy requirements, a weight gain or loss will occur. If an athlete is maintaining his or her ideal competitive weight, adequate calories are being consumed.

A number of factors shape the calorie intake of adolescent athletes. Many young female athletes are concerned about their appearance and eat less than they should in an attempt to appear thin. However, restricting calories can have a negative impact on both health and performance because, as calorie consumption decreases, so does nutrient consumption. The minimum requirement for high school athletes should be roughly 1800-2000 calories a day. Athletes eating less than 1800 calories a day likely consume insufficient amounts of vitamins, minerals, and protein. This can leave them feeling weak and listless.

Some athletes find it difficult to increase their calorie consumption because the bulk of a larger meal causes them discomfort, especially if they are training soon after eating. On the other hand, athletes juggling a heavy academic load with training and a part-time job often find they have no time to eat. For these athletes, eating several small meals and snacks becomes an important source of nutrients.

CARBOHYDRATES
Carbohydrates are an important energy source for both health and performance. Although carbohydrate foods such as breads, cereals, rice, pasta, vegetables, and fruit contribute essential vitamins, minerals and fiber, their major contribution to an athlete's diet is to supply energy for training and competition.

Although muscles need energy to perform, the body has a limited ability to store carbohydrate as readily utilized glycogen. When athletes don't eat enough carbohydrate, their glycogen stores quickly become deleted, and the result is fatigue or a feeling of staleness.

Like calories, carbohydrate needs vary among athletes, depending on the intensity and volume of training, body size, and event specialty. Throwers, sprinters, jumpers, and pole vaulters engaged in explosive events requiring short bursts of energy need about 5 grams of carbohydrate per kilogram of body weight (or a minimum of 250 grams) per day to maintain their muscle glycogen stores. Athletes who compete in events requiring a longer, sustained expenditure of energy may need more - up to 8-10 grams of carbohydrate per kilogram body weight daily for marathon runners.

To determine how much carbohydrate an individual athlete needs, divide his or her body weight in pounds by 2.2 to get the weight in kilograms. Then multiply that number by 5 to 8. depending on event and training demands.

For example:
150 pounds ÷ 2.2 = 68 kilograms of body weight
68 kilograms x 5 = 340 grams of carbohydrate needed

Carbohydrate is found in two forms, starches and sugars. Starch, such as potatoes, rice, pasta, breads, and cereals, is a complex carbohydrate. Sucrose (table sugar), the lactose in milk products, and the fructose in fruit and juices are simple carbohydrates. Both types of carbohydrate are effective in replenishing glycogen.

PROTEIN
The body uses protein for muscle repair and growth. It also provides energy during long endurance events. Athletes have a slightly higher protein need than non-athletes, but this demand is usually met by a normal diet unless they already aren't getting enough calories. Protein requirements increase when calorie consumption is insufficient to meet the body's needs because some of the consumed protein must be metabolized to provide energy instead of building and repairing tissue.

Current research on protein requirements suggests athletes need approximately 1.0-1.5 grams of protein per kilogram of body weight daily. For a 150-pound (68 kilogram) athlete, that is 68-102 grams of protein a day. This amount is adequate for athletes who are involved in both explosive and endurance events.

The type of protein eaten also affects the amount of protein needed. The 1-1.5 grams per kilogram of body weight recommendation is based on a diet containing animal proteins. An athlete who eats meat, fish, poultry, cheese, milk, yogurt or eggs will have little problem meeting his or her protein needs. Athletes who are strict vegetarians, however, will need to plan their diets more carefully to meet protein requirements, which may be as high as 2.0 -2.5 grams per kilogram of body weight.

PROTEIN SUPPLEMENTS
Amino acids are the building blocks of protein. The body uses 20 amino acids to synthesize tissue proteins, nine of which must be obtained from the food we eat. Amino acid supplements have become popular among some athletes because they have been told they will improve performance, supply extra energy, and increase muscle mass.

However, extensive research has not been able to show that amino acid supplements have any beneficial effects on athletic performance. Many athletes already eat more than the recommended amount of protein, consuming far more amino acids than needed from their diet alone. Since the body cannot store extra protein, excess protein is broken down and stored as fat, as are all extra calories.

FAT
All athletes need a certain amount of fat in their diets and on their bodies. The challenge is eating a diet that provides the right amount. The American Heart Association recommends that no more than 30% of our calories come from fat. Because athletes differ, some may require slightly less than 30% of their calories from fat.

Fat provides certain vitamins and minerals and adds flavor to food. Many athletes cannot get the calories they need without consuming some extra fat. On the other hand, too much fat contributes excess calories to the diet which can lead to weight gain. High-fat diets also increase the risk of heart disease and some cancers. Moreover, athletes who have a high-fat diet often eat less carbohydrate, which is detrimental to good health and high performance.

To lower fat intake, athletes should choose lean meats, fish, poultry, and low-fat dairy products. Fat and oils should be used sparingly in cooking. Fried foods and high-fat snacks should be avoided.

VITAMINS
Vitamins are nutrients needed in small amounts for normal metabolism, growth, and development. Although vitamins do not serve as a direct source of energy, they help metabolize energy from carbohydrate, protein, and fat. Taken in excess, vitamins provide no performance enhancement to the athlete who is healthy and eating a balanced diet.

In fact, excessive vitamin supplements can be harmful. For example, the recommended dietary allowance (RDA) for vitamin A is 1,000 retinol equivalents (RE) for men and 800 for women. As little as five times these amounts can cause severe headaches, bone and joint pain, dry flaky skin, and even liver damage. Generally, athletes who consume more than 1800 calories a day get enough vitamins from their food. However, a vitamin/mineral supplement supplying 100 percent of the RDAs may be appropriate for athletes with extremely low calorie intakes or for those who avoid certain basic food groups.

MINERALS
Minerals perform major functions in the body. First, they are used as building blocks for tissue growth of bones, teeth, muscles, and red blood cells. Second, minerals activate several of the body's enzymes and hormones. Minerals are often classified as macronutrients, minerals present in relatively large amounts in the body, such as calcium, phosphorus, and magnesium, or as micronutrients or trace minerals, such as iron, copper, and zinc, which are present in small amounts in the body. Minerals play an important role in managing exercise. They help maintain normal body fluid balance, muscle contraction, and blood clotting. A balanced diet sufficient in calories should provide adequate levels of minerals. While a nutrient-by-nutrient review is not necessary for the purposes of this document, iron and calcium deserve some special mention because of the importance of these two minerals in an athlete's diet.

Iron is crucial for athletes because it assists oxygen transport in the blood and utilization by the muscles. A lack of iron directly affects performance by decreasing the capacity of muscle to use oxygen. Young female athletes, in particular, are at risk of iron deficiency because of increased iron losses through menstruation and typically low dietary iron intake. It is recommended that female athletes have hemoglobin levels checked at least once a year.

Exercise, especially running, contributes to iron depletion in both adolescent male and female athletes. With heavy training, there is an increase in plasma blood volume, which dilutes the number of red blood cells and lowers hemoglobin levels. The impact of thousands of hard foot strikes also destroys red blood cells and can contribute to iron deficiency among distance runners.

Supplemental iron may be prescribed for individuals whose lab tests indicate iron deficiency. However, a routine use of iron supplements by all athletes is not recommended.

Athletes should be aware of the foods which provide iron. Their diets should contain at least 1-2 servings of meat, green leafy vegetables, or fresh fruit each day. The use of enriched cereals and breads provides additional iron. Vitamin C-rich foods, such as orange juice, enhance iron absorption. The RDA for iron is 15 milligrams a day for females,and 10 milligrams a day for males.

CALCIUM
Calcium is important not only because of its role in preventing osteoporosis (bone deterioration), but also because it helps maintain bone density, which prevents stress fractures. Young women who train strenuously to the point of amenorrhea (absence of menses) are susceptible to such bone loss. This is a serious health risk. Once bone matter is lost, it can never be regenerated.

An athlete's calcium needs are greatest during adolescence, when the bones are growing. Inadequate dietary calcium increases the risk of brittle bones in some individuals. If an athlete does not consume at least four servings of calcium-rich foods such as milk, cheese, yogurt, or green leafy vegetables each day, a calcium supplement may be necessary. The diet should be evaluated before calcium supplements are taken. The RDA for calcium is 1200 milligrams a day for males and females ages 11-18 years old. One glass of 2% milk contains 300 milligrams of calcium.

Pre-Competition Meals
The primary purpose of the pre-competition meal is to provide fluid and energy for the athlete during the performance of his or her event(s). Since many athletes experience abdominal discomfort if they have food in their stomachs during competition, the timing of the pre-competition meal is important. In most cases, the athlete will feel quite comfortable if the meal is eaten 2-3 hours prior to competition. However, some runners find they need to eat something as close as 30 minutes prior to their event.

Pre-competition eating requirements vary greatly from athlete to athlete, and they must understand that the pre-meet eating regimen of the current Olympic champion in their event may not work well for them.

The primary requisites ofthe precompetition meal should be.

• That it consists of foods the athlete likes and tolerates easily.
• That it consists of foods the athlete usually eats.
• That it includes the consumption of plenty of fluids. The day of competition is not the time to experiment with new foods.

Athletes may have to do some advance planning to ensure they have access to their familiar foods before competition. They may need to bring a sack lunch to school rather than choosing from the school cafeteria's entrees or a restaurant menu. Eat foods you believe will help you win. Eating foods you do not like before competition, or depriving yourself of usual foods in an effort to enhance performance, almost always has a negative outcome.

It cannot be overemphasized that the ideal pre-competition meal is a matter of individual preference. The pre-competition meal should consist of food and beverages the athlete likes and enjoys, tolerates well, ordinarily eats, and thinks will help him or her win.

Achieving Ideal Competitive Weight
Weight control is a problem for many athletes. While some struggle to keep weight on, others fight to keep pounds off. Genetics, age, and training all affect body weight. Diet and lifestyle also play an important role. Young athletes with busy schedules tend to have irregular eating habits and sleeping patterns. As a result, gaining weight or keeping it on can be a problem. Most often, it is simply a matter of not getting enough calories. Making changes in the amount and types of food eaten and increasing the frequency of meals usually solves the problem. Athletes who want to gain weight need to eat at least five times a day.

For athletes trying to lose weight, eating less will decrease calorie intake. However, if calorie intake drops too low, the body will compensate by reducing its metabolic rate and reducing the number of calories needed. This sabotages the athlete's attempt to lose weight. Increasing your activity level in conjunction with reducing calories usually results in weight loss.

Paying attention to the amount and types of food eaten is important. Eating fewer high-fat foods such as fried foods, gravies, sauces, high-fat snacks, and desserts can significantly reduce calorie intake. The recommended rate of weight loss is one-half pound a week, which requires a deficit of 250-300 calories a day. A safe level of calorie restriction depends on the athlete's normal dietary intake. Males should not consume fewer than 2000 calories a day. Females should not consume fewer than 1800 calories a day.

-by Ann C. Grandjean, Ed.D.
International Center for Sports Nutrition