Athletes should know how nutrition affects growth, health, and physical and mental performance. The best sports performance comes from good nutrition. Balanced diets should include energy foods, which are fats, proteins, and carbohydrates such as starches and sugars. They should also include vitamins, minerals, and enough fluids.
Good nutrition means eating daily grains, fruits, vegetables, beans, lean meat, and low-fat dairy products. Drinking fluids prevents dehydration, which causes poor athletic performance.
Young athletes may think that a poor diet is not harmful, but bad eating habits may be hard to stop later and can cause disease. Some athletes also overexercise or use dangerous purging, diuretics, or laxatives to lose weight.
Many things—age, sex, genetics, body size and weight, and training frequency, duration, and intensity—affect energy in-take. The food guide pyramid is an excellent starting place for planning a balanced diet. Refueling with carbohydrates and small amounts of protein immediately after exercise can help in replacing energy stores (muscle glycogen) more effectively and thus improve performance.
The body changes carbohydrates into glucose (sugar) for energy. Carbohydrates include starches (in vegetables, grains, pasta, cereals), sucrose (table sugar), fructose (fruits, juices), and lactose (milk sugar). Usually, two thirds of an athlete’s plate should be carbohydrate-rich foods, not processed or convenience foods (e.g., chips, candy, pizza).
About one third of an athlete’s plate should be protein-rich foods (meat, beans, eggs). Eat from different plant and animal sources to get all essential amino acids (proteins), vitamins, minerals, and antioxidants. Well-planned vegetarian diets can also provide enough energy and nutrients.
Some dietary fat is important. Meats, cheeses, nuts, and oils (olive, canola, fish) provide fat. Avoid high-fat foods (whole milk, fatty beef, fried foods), which can lead to heart disease, diabetes, and obesity. Also avoid very low fat diets because some vitamins are fat soluble vitamins and can only be obtained by ingesting dietary fat.
A balanced diet can meet vitamin and mineral needs, but supplements (calcium, vitamin D) may sometimes be needed.
Dehydration is the most common reason for poor performance, but it’s also the most preventable. Drink water as well as fluids that have electrolytes in them, because they can help the body hold on to water. Drinking large quantities of water, without electrolytes, can be very dangerous. Don’t rely on thirst to signal fluid needs; when you’re thirsty you’re already dehydrated. Acute dehydration can occur in 2 to 3 hours (marathon runners, triathletes). Chronic dehydration (days of not enough fluids) may be even more dangerous. It’s often seen during preseason soccer or football training. Infrequent urination, dark yellow urine, headache, and weakness may mean dehydration.
Follow eating guidelines for before, during, and after exercise. Always drink enough fluids. Eat a high-carbohydrate, low-fat meal (grains, pasta, potatoes, fruits, and vegetables), with lean protein, 3 to 4 hours before an event. Shortly before an event, eat easy-to-digest high-carbohydrate foods (bananas, bagels) and drink cool water. These prevent cramping, diarrhea, and hunger pains during an event. During exercise, drink 1/2 cup of water every 20 minutes. For long exercise (more than 90 minutes), sports or sugary drinks can fuel muscles. More fuel (high-carbohydrate foods) may be needed right after exercise, and then a balanced meal within 2 hours. For repeated bouts of prolonged exercise, it is helpful to increase the salt intake during meals to help the body maintain fluid balance.
Athletes who need to lose body fat should do so in the off-season. Don’t lose too much too fast: 0.5 to 1.0 pound/week (lean and normal weight), up to 2 pounds/week (excess body fat). Athletes who need to gain weight can use resistance training and increased calorie intake.
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Copyright © 2016 by Saunders, an imprint of Elsevier, Inc.
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