Nutrition for Athletes

Photo of a woman in athletic wear blending a nutritional smoothie

Top athletic performance requires talent, training, and plenty of fuel.

Proper nutrition is essential for athletes, but what that looks like can sometimes seem elusive or mysterious.

So what can an athlete do to optimize their diet in order to achieve their performance goals?

Essential Nutrients for Athletes

The nutrients that are essential for athletes are the same ones that are essential for everyone, just perhaps in increased amounts. Athletes need carbohydrates, fats, protein, vitamins, minerals, and water.

They need to consume a balanced diet that includes a wide variety of foods to ensure that they get enough of all these nutrients.

For most people, even those who exercise more than the average person (think 30-40 minutes most days of the week) the same healthy diet recommendations apply as for the general public. Elite athletes who participate in high-intensity training programs, however, do often need to increase their intake of food overall to meet their higher requirements for energy and nutrients.


Carbohydrates are the primary source of energy for athletes and non-athletes alike. About half of the energy a person takes in should be from carbohydrates, and since athletes burn more energy than the average person, it stands to reason that they need to take in more carbohydrates as well.

During exercise, both carbohydrates and fats are utilized as fuel. During higher intensity exercise, the body uses more carbohydrates than fat because burning carbohydrates is more oxygen-efficient (1).

The body stores carbohydrates in the form of glycogen in the muscles and liver. During intense exercise, the body draws on these stores, converts the glycogen to glucose, and then metabolizes the glucose to release energy. The body’s stores of glycogen are finite, and most of the time they are sufficient to last the athlete through a training session or competition.

When an event requires greater than 60 minutes of intense activity or when the athlete has not consumed enough food leading up to the exercise, it may be beneficial to replace carbohydrates along with fluid and electrolytes during the event or training session. This can be done using a commercial or homemade sports drink.

Current recommendations for carbohydrate intake for people participating in high- and very high-intensity training regimens range from 6 to 12 grams of carbohydrate per kilogram of body weight (g/kg) per day (2) (3).

An individual athlete’s needs will vary depending on age, sex, the type and intensity of training or sport, environmental conditions, and total energy expenditure.

Normally, carbohydrates should make up 45-55% of total energy intake, but at certain times, such as when you are trying to replenish your glycogen stores, you may need more than that.

If you know your weight in pounds, divide that by 2.2 to get your weight in kilograms. Then multiply that by 6-12 and you will get a range in grams of carbohydrates that you should aim to take in each day. This will probably give you quite a wide span.

If you have a more individualized number given to you by a coach or sports dietitian, then you’ll be able to narrow it down to a more specific range. Your individual goal may even vary from day to day depending on your training and competition schedule.

Alternatively, if you know the total number of calories you burn each day (which also may vary depending on your training schedule) you can multiply that by 45-55% to get your number of calories from carbohydrate. During times when you are trying to replenish your glycogen stores after an intense competition, that number may be 60% or greater.

When you have the number of calories, divide that by 4, because there are 4 calories per gram of carbohydrate. Then you’ll have a number of grams of carbohydrate to aim for.

Carbohydrate Loading and Glycogen Replenishment

Current evidence suggests that 5-6 grams of carbohydrates per kg of body weight per day should be enough to sustain glycogen stores at normal levels during routine training, which is at the low end of the recommended range for athletes in general. (4)

Some types of competition require incredible endurance, and athletes need to have their glycogen stores at maximum levels to avoid tiring out or underperforming. In this situation, consuming 8-10 g carbohydrate per kg of body weight per day plus resting for 24-72 hours before the competition is believed to be able to “supercompensate” (increase or expand) glycogen stores to their maximum levels. (5) This practice is called carbohydrate loading.

After a competition or a particularly intense period of training, athletes need to replenish the glycogen that they have depleted.

In some cases, they may need to replenish it rapidly, such as during competitions that involve multiple trials or rounds in the same day. In this situation, it is recommended to consume 0.5-0.6 g carbohydrate per kg body weight every 30 minutes for 2-4 hours or until the next full meal. Otherwise, 6-12 g/kg per day for 24-36 hours is generally enough to replace what was used up.

Whether an individual needs closer to 6 g/kg or closer to 12 g/kg will depend mostly on the intensity and duration of the exercise that depleted the glycogen stores. (6)

Good sources of carbohydrates for athletes include minimally processed grains, fruits, starchy vegetables, legumes, and dairy. These carbohydrate-rich foods also provide other nutrients such as fiber, vitamins, minerals, and protein.

In the hours immediately following exercise, carbohydrates that absorb more quickly (that are lower in fiber) may help replenish glycogen stores more effectively. Similarly, soon before exercise, high fiber, fat, or protein foods like whole grains may not be as well tolerated because they take longer to digest and may cause abdominal discomfort during the exercise. The rest of the time, however, it is recommended to choose carbohydrate sources that are also rich in fiber and to pair them with healthy fats and protein.

Some examples of carbohydrate-rich foods with carbohydrate content:

  • Bread: around 12-15 grams per slice
  • Pasta: around 30 grams per cup (cooked)
  • Rice: around 45 grams per cup (cooked)
  • Potatoes: 30-40 grams each (small to medium size)
  • Lentils or beans: around 40-45 grams per cup (cooked)
  • Banana (medium-sized): around 30 grams each
  • Orange or apple: around 15 grams each
  • Milk: 12 grams per 8 oz cup


Fat is also an important fuel source for athletes. The body is always burning a combination of carbohydrates and fat for energy, but the proportions of each change. Fat is utilized at higher rates during lower-intensity exercise, and also during exercise of long duration. Once the body’s carbohydrate stores are on their way to being depleted, it will turn more to fat for energy to preserve glycogen.

As a result of aerobic training, athletes often transition to burning more fat sooner than the average person during exercise. (7) (8)

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