Nutrition and athletic performance


Nutrition can help enhance athletic performance. An active lifestyle and exercise routine, along with eating well, is the best way to stay healthy.

Eating a good diet with enough fluids can help provide the energy you need to finish a race, or just enjoy a casual sport or activity. You are more likely to be tired and perform poorly during sports when you do not get enough:

  • Calories
  • Carbohydrates
  • Fluids
  • Iron, vitamins, and other minerals
  • Protein

Alternative Names


Food Sources

Side Effects


The diet recommended for an athlete is not very different from the diet recommended for any healthy person.

However, the amount of each food group you need will depend on:

  • The type of sport
  • The amount of training
  • The time you spend in the activity or exercise

To help you perform better, avoid exercising on an empty stomach. Everyone is different, so you will need to learn:

  • How soon before exercising is best for you to eat
  • How much food is the right amount for you


Carbohydrates are a diet staple. They are important for providing energy during exercise. Carbohydrates are stored in the body in the form of glycogen, mostly in the muscles and liver.

Complex carbohydrates are found in foods such as pasta, bagels, whole grain breads, and rice. They provide energy, fiber, vitamins, and minerals and are low in fat.

Simple sugars such as soft drinks, jams and jellies, and candy provide a lot of calories, but they do not provide vitamins, minerals, and other nutrients.

What matters most is the total amount of carbohydrates you eat each day. A little more than half of your calories should come from carbohydrates.

You need to eat carbohydrates before you exercise if you will be exercising for more than 1 hour. You might have a glass of fruit juice, a cup of yogurt, or an English muffin with jelly.

During exercise, you also need carbohydrates. You can satisfy this need by having:

  • Five to 10 ounces of a sports drink every 15 to 20 minutes
  • Two to three handfuls of pretzels
  • One-half to two-thirds cup of low-fat granola

After exercise, you need to eat carbohydrates to build the glycogen storage back up in your muscles.

  • Within 30 minutes, eat a granola bar, small bagel with jelly, or sweetened cereal, or drink 12 to 16 ounces of an energy drink or fruit punch.
  • People who exercise or train for more than 90 minutes should eat or drink more carbohydrates, possibly with protein, 2 hours later. Try a sports bar, trail mix with nuts, or yogurt and granola.


Protein is important for muscle growth and to repair body tissues. Protein can also be used by the body for energy, but only after glycogen or carbohydrate stores have been used up.

Many people feel athletes need a high-protein diet to support muscle growth, yet researchers have found this to be false.

It is also a myth that a high-protein diet will promote muscle growth. Only strength training and exercise will change muscle. Athletes, even body builders, need only a little bit of extra protein to support muscle growth. Athletes can easily meet this increased need by eating more total calories (eating more food).

Most Americans already eat almost twice as much protein as they need, so protein needs for muscle development are already met. Too much protein in the diet:

  • Will be stored as increased body fat
  • Can increase the chance for dehydration (not enough fluids in the body) and loss of calcium

Often, people who focus on eating extra protein may not get enough carbohydrates, which are probably the most important source of energy during exercise.

Amino acid supplements and eating a lot of protein are not recommended. They can increase calcium loss and put an added burden on the kidneys, which must remove the excess nitrogen that protein provides.


Water is the most important, yet overlooked, nutrient for athletes. Water and fluids are essential to body hydrated and at the right temperature. Your body can lose several liters of sweat in a 1-hour period.

Clear urine is a good sign that you have fully rehydrated. Some suggestions for keeping enough fluids in the body include:

  • Make sure you drink plenty of fluids with every meal, whether or not you will be exercising.
  • Drink about 16 ounces (2 cups) of water 2 hours before a workout. It is important to start exercising with enough water in your body.
  • Continue to sip water during and after you exercise -- about 1/2 to 1 cup of fluid every 15 to 20 minutes. Water is best for the first hour. Switching to an energy drink at that time will help you get enough electrolytes.
  • Drink even when you no longer feel thirsty.
  • Pouring water over your head might feel good, but it will not get fluids into your body.

Offer children water often during sports activities. They do not respond to thirst as well as adults.

Adolescents and adults should replace any body weight lost during exercise with equal amounts of fluids. For every pound you lose while exercising, you should drink 24 ounces or 3 cups of fluid within the next 6 hours.


Changing your body weight to improve performance must be done safely or it may do more harm than good. Keeping your body weight too low, losing weight too quickly, or preventing weight gain in an unnatural way can have negative health effects. It is important to set realistic body weight goals.

Young athletes who are trying to lose weight should work with a registered dietitian. Experimenting with diets on your own can lead to eating disorders and poor eating habits.

Speak with a health care professional to discuss a diet that is right for your sport, age, gender, and amount of training.


Bonci L. Nutrition, pharmacology, and psychology in sports. In: DeLee JC, Drez D Jr, Miller MD, eds. DeLee and Drez's Orthopaedic Sports Medicine. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2009:chap 8.

Position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Journal of the American Dietetic Association. March 2009. 109(3);509-527.