Athletes who participate in endurance sports have particular nutrition requirements that differ from those involved in more general sporting codes. In this article, we discuss how young athletes can optimise their nutrition intake to maximise sport performance.
In addition to meeting nutrition requirements for growth and development, the endurance athlete also has other considerations regarding performance nutrition. Carbohydrate intake is especially important for endurance athletes as carbohydrates are the body’s number one preferred energy source. If carbohydrate intake is insufficient, this will result in fatigue, and reduced exercise performance and recovery.
As a minimum, the endurance athlete’s diet should be made up of approximately 45-65% carbohydrates, protein of 1.2-2.0 grams per kg per day, and fat being 20-35% of total energy, with a maximum of 10% total energy coming from saturated fats and trans fats. Carbohydrate and protein intake will vary depending on the volume (amount) and type of training a young athlete is involved in.
Below we highlight some major areas of consideration for the young endurance athlete.
Because the body uses carbohydrate as its preferred source of energy, intake needs to at least provide enough energy to support training load and recovery. There is significant evidence that supports a high carbohydrate diet for athletes who compete in endurance-based sports, and for those who compete in intermittent high intensity-based sport (for example squash, tennis, rugby).
For sport nutrition, carbohydrates are measured in grams per kg. General guidelines for carbohydrate intake are shown in the table below.
|Training Intensity||Training Volume||Carbohydrate Target|
|Light||Low intensity or skill-based training||3-5g/kg of bodyweight per day|
|Moderate||Training up to 1 hour per day||5-7g/kg of bodyweight per day|
|High||Endurance training 1-3 hours per day at moderate to high intensity levels||6-10g/kg of bodyweight per day|
|Very High||Training greater than 4-5 hours per day at moderate to high intensity levels||8-12g/kg of bodyweight per day|
Examples of carbohydrate foods include rice, pasta, bread (grain bread preferred), fruit & vegetables, beans, lentils, quinoa, porridge, Weet-Bix, untoasted muesli.
Carbohydrate intake varies according to the type and intensity of training an athlete is involved in. The Food Cruncher has designed a sport nutrition plan for young athletes that lets them work out their own carbohydrate intakes using digital calculators, based on training load and volume. See here for more information on this new sport nutrition programme.
Endurance athletes need to pay attention to their fluid intake. A reduction in bodyweight of greater than 2% can reduce athletic performance, especially in hot weather. In a cool environment, reduction in exercise performance can be seen with bodyweight loss of around 3-5% due to dehydration. Dehydration can result in increased heart rates and body temperature and can also reduce concentration and the ability to make decisions.
Below is a guideline for fluid intake before, during, and after exercise.
|Before Exercise||5-10ml/kg of bodyweight||2-4 hours before training|
|During Exercise||0.4 – 0.8L||Per hour|
|After Exercise||1.25 – 1.5 L fluid for every kg of lost bodyweight||As soon as possible after training|
One of the most important considerations regarding fluid intake is that the young athlete starts from a well hydrated position. Body weight should be monitored to assess weight gain or loss after training.
Athletes who drink too much during training or competition, will gain weight. Although over-hydration is a consideration for athletes, dehydration is usually more common. Young athletes need to practice their hydration strategies during training to ensure they remain optimally hydrated for their endurance events.
Sodium (salt) replacement
Low salt levels as a result of exercise can cause serious health issues. Signs of low sodium levels include headache, vomiting, swollen hand & feet, restlessness, confusion, fatigue.
Sports drinks often have salt (sodium) added to them. Consuming these should alleviate concerns around sweat loss and exercise performance. Note that water is generally an adequate replacement for training lasting less than 90 minutes.
Salty snacks after training will also help. Foods such as pretzels, pizza, salted nuts, canned soups, and baked beans would be suitable for replacing salt levels after an endurance event. Alternatively, adding a little salt (1/4 a teaspoon) to a glass of orange juice would also help supplement low sodium levels.
Because sweat levels are highly variable, it is not possible to provide a general salt replacement guide that will fit all situations. Consuming a sports drink or having a salty snack after training should be enough to replace any sodium losses during exercise.
Protein allows for muscular repair and adaptation. Requirements for the young athlete range between 1.2-2.0 grams per kg per day. However, this is highly variable depending on an athletes training load (volume) and sport.
Protein should come from lean meat (skin and fat removed), fish, low fat dairy products (milk, yoghurt, cheese), vegetarian and vegan sources include (lentils, chickpeas, beans, tofu), and should be spread out across the day over 3-5 meals. As a general guide, 15-25 grams of high-quality protein after training should be sufficient to allow for muscular adaptation, repair, and recovery.
Vegans need to ensure they are eating grains (barley, brown rice, buckwheat, bulgur, oats, whole-wheat bread and pasta) AND legumes (lentils, peas, chickpeas, beans, peanuts) together OR nuts & seeds and legumes together after training to ensure they meet their complete protein requirements.
A well-constructed vegetarian or vegan diet will meet all the protein requirements needed for health and training, however after training it is important to combine protein sources to ensure a complete protein profile is achieved. This will allow for better muscular repair, adaptation and recovery from training.
Fat intake should make up 20-35% of an athlete’s energy intake. No more than 10% of energy intake should come from saturated and trans fats. Saturated and trans fats come from foods like butter, cream, cheese, meat fat, coconut products (oil, cream, milk), palm oil, and processed foods like cakes and biscuits (supermarket), pies, donuts, sausage rolls, and deep-fried foods.
Always choose unsaturated fats where possible. These include plant-based oils such as olive, rapeseed, peanut, sunflower. Unsaturated fats are heart healthy and can be found in foods such as avocados, nuts & seeds, flaxseed oils, walnuts, and oily fish like salmon and sardines.
The bottom line on macronutrients (carbohydrates, protein, and fat)
Endurance athletes need to pay attention to their carbohydrate intake to ensure they are eating enough to allow for training and recovery. Protein is important to allow for muscular repair and adaption and should be spread out across 3-5 meals during the day. Fat intake should be between 20-35%, with a maximum of 10% of energy coming from saturated and trans fats combined.
A word on supplements. Unless training is longer than an hour, water and/or milk will be sufficient to support training and recovery. If training is longer than an hour, Gatorade or Powerade is probably safe. Energy drinks are not. Do not take them. If you are unsure what your young athlete should be taking, check with your coach as it is always the athlete’s responsibility to know what they put into their body.
The Food Cruncher has designed a sport nutrition programme for young athletes aged 12-18. This lets them work out their own carbohydrate, protein, and fat requirements using digital calculators. There are also example meal plans and lots of recipes to use. See here for further information.
Thomas DT, Erdman KA, Burke LM. Nutrition and athletic performance. Med. Sci. Sports Exerc. 2016 Mar;48:543-68.
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The Food Cruncher provides a digital nutrition platform aimed at reducing the incidence of obesity, type 2 diabetes, cardiovascular disease, and depression using evidence-based nutrition information. The Food Cruncher also provides evidence-based sport nutrition guidelines for both adults and young athletes.
Michelle Redmond is the co-founder of The Food Cruncher and uses evidence-based nutrition information to help inform people to improve their long-term health outcomes.
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