There are two groups of nutrients that make up what we eat and drink: Macro- and micro-nutrients. Macronutrients include carbohydrates, lipids, and proteins. These nutrients provide the energy necessary to maintain body functions during rest and physical activity. Micronutrients are vitamins and minerals that play highly specific roles in facilitating energy transfer and tissue synthesis.
Carbohydrate-rich foods are the best fuel sources for athletes. Athletes need 55 to 65 percent of their calories to come from carbohydrates. Carbohydrates are classified as “simple” or “complex”. Simple carbohydrates are typically associated with sweet foods and ripe fruits. Complex carbohydrates such as starches should make up the majority of carbohydrate fuel. Complex carbohydrates usually carry with them other nutrients, such as the B vitamins. Examples of starchy foods are breads, cereals, pastas, and starchy vegetables such as corn, potatoes, dried beans and peas. Fruits are also excellent sources of carbohydrates. Obtaining carbohydrates from a variety of sources is very important.
Carbohydrates are the initial fuel source and are the primary fuel source in short-burst, high-intensity events. Activities such as sprinting, jumping, hitting a ball, and pole vaulting are fueled 100 percent by carbohydrates.
The body is able to store carbohydrates in limited amounts as glycogen. Athletes are able to store more glycogen and use its limited supply sparingly if their diet is rich in complex carbohydrates and through proper training. The amount of glycogen storage is about 1800-2000 calories. When glycogen stores are exhausted, then athletic performance suffers. Glycogen requirements for endurance athletes are slightly higher than the typical athlete.
Lipids, or fats are another important source of fuel. Fats also carry fat soluble vitamins (vitamins A, D, E, and K). They have over twice as many calories as an equal weight of carbohydrates. Aerobic training increases the body’s ability to use fat as an energy source, so glycogen can be spared. Fats cannot be used as an exclusive fuel. The body’s fat storage is more than adequate to supply the energy needed for activity, so it is not necessary to supplement fat into your diet. In fact, a diet that is moderately low in fat (no more than 30 percent of total calories from fat) will not hinder the athlete’s performance and will promote a healthy eating style that will be beneficial to the athlete in the future. Since fats are such a concentrated source of energy, reducing fat intake makes it possible for an athlete to eat much more food to provide other nutrients to your body.
Some simple steps for reducing fat intake include: consume little or no fried foods, avoid prepared meats (bologna, salami, bacon, sausage, etc), and limit the consumption of visible fats (butter, margarine, fat surrounding steak, chicken skin, etc.). Instead, select lean meats and low-fat dairy products to avoid saturated fats. Excess dietary fat is very efficiently and easily converted to stored body fat. Fats are metabolized during exercise, but it takes time and aerobic training to become an efficient fat “burner”. Again, don’t eliminate fat from the diet; rather take some simple steps to reduce it.
Saturated fats occur in animal products like beef, pork, chicken, egg yolk, and in dairy fats of cream, milk, butter, and cheese. These are looked at as unhealthy forms of fat. Unsaturated fats are those that occur in canola oil, olive oil, peanut oil, and the oil in almonds, pecans, and avocados. These are generally looked at as healthier forms of fat.
Protein is essential to the human body for growth and repair of tissue. Protein also helps athletes regulate metabolism and is used as an energy source when calories from fat or carbohydrates are deficient. Protein is made up of chains of amino acids, some of which the body cannot manufacture. Amino acid supplements are unproven and expensive. Adequate amounts of protein can be obtained through a healthy diet. Unlike carbohydrates, protein cannot be stored in the body and any excess will be burned for energy or stored as body fat.
In general, 0.8 grams of protein per kilogram of body weight per day is the recommended amount for protein intake. (Divide your weight in pounds by 2.2 to get your weight in kilograms.) Athletes have an increased requirement for protein that is determined by duration and intensity of exercise, degree of training and the amount of energy and protein intake of the current diet. Athletes who train hard need additional protein in their diet. This can usually be achieved as easily as eating a can of tuna, proving that spending money on expensive supplements is unnecessary. Adequate carbohydrate intake is essential for proper utilization of protein in the body.
Strength athletes need 1.4 to 1.8 grams of protein per kilogram of body weight per day. This extra protein is needed to increase muscle weight. Runners and other endurance athletes also need more protein because during long workouts their muscles will use protein as an energy source. These athletes need 1.2 to 1.4 grams of protein per kilogram of body weight per day. In general, endurance athletes weigh less than strength athletes, so the actual amount of protein needed is less. For example, a 200-pound linebacker needs 127 to 163 grams of protein per day; where as a 160-pound cross-country runner may need 87 to 101grams of protein per day. Children and adolescents who are growing have a slightly higher need for protein than adults. It is recommended that moderate exercisers take in an additional 10 percent of protein above their RDA.
Too much protein can be a problem. Extra calories, no matter what the source, can be converted to stored body fat. If protein intake exceeds the recommendations then the liver and kidneys must work harder to rid the body of unwanted byproducts. This increased stress can lead to health problems including dehydration, loss of calcium, and liver and kidney problems in the future.
Protein powders and liquids are very popular in athletes and body builders. Athletes should know their protein goals and exactly how much they actually get in their diets. Athletes should only try supplementing protein into their diet only after they have had problems obtaining the correct amount of protein through modifications in their current diet. Shakes and protein bars are convenient methods of protein intake for athletes, but long-term studies have not been performed and the expense of them is not always worth the trade off. For example, most protein supplements contain 20 to 50 grams of protein and cost between $20.00 and $50.00 a canister. A can of tuna provides 37 grams of protein and costs less than $1.00. As stated earlier, a balanced diet that is modified for protein requirements is the most effective method of getting protein into the body.
Adequate carbohydrate intake is necessary to provide energy, so the protein consumed will be used for all valuable functions instead of being “burned” as a fuel source. Burning protein as a fuel causes increased water loss that can increase the risk of dehydration.
Most of the attention in a nutritional plan must be paid to the macronutrients. Athletes have an increased need for adequate calorie intake, but special attention must be paid to ensure that these calories come from the proper nutrients.