Athletes require more calories and nutrients than normal people.  In particular, young adolescent athletes require more than normal athletes because they need to account for growth and replenishment of nutrients used while competing.  Nutrition can be a complex issue for many parents of student athletes.  Knowledge of how many calories, how many grams of protein, how many grams of fat, how many grams of carbohydrates, or how many ounces of water may be difficult to find information on, let alone estimate.  On top of that, knowing where to find these nutrients in a daily diet gets even more complicated.

Protein is one of the most important nutrients athlete can consume.  They are made up of amino acids and make up the building blocks of our muscles.  As the athlete trains to be bigger, fast, or stronger, their muscles undergo significant stress and strain.  This leads to breakdown of muscle tissue, which is a normal process for increasing size and strength of given musculature.  You may know this feeling of breakdown as the soreness after a particularly difficult workout or after trying to pick-up exercising on January 1st!  We call this Delayed Onset Muscle Soreness, or DOMS for short.  DOMS is not necessarily a bad thing, but your body does require enough protein to help build and repair that muscle.  An athlete will be sore many times throughout the initial conditioning process in preparing for a sports season and making sure that athlete takes in enough calories.

Fats are easy!  They’re fats.  We find them in butter, whole milk, cheese, yogurt, fish products, and generally in most foods we eat daily.  Growing athletes require enough fat in their diet to properly form tissues in their bodies, which is often the opposite of what you might hear in the media.  It’s always “low fat” you see marketed to the public.

In an article published in the Journal of Sports Medicine in 2015, estimates for total calories consumed by athletes based on age and sex are as follows:2

 Age (Years)  kCals (Boys)  kCals (Girls)
 6-7  1800  1650
 7-8  1950  1775
 8-9  2100  1950
 9-10  2275  2125
 10-11  2475  2300
 11-12  2700  2475
 12-13  2925  2625
 13-14  3175  2725
 14-15  3450  2855
 15-16  3650  2875
 16-17  3825  2875
17-18  3925  2875

Breakdown of estimated percentages of these caloric numbers into three groups is necessary to identify how much of each substrate (fats, proteins, carbohydrates) your athlete needs in their diet.  As young athletes grow, they need enough calories in their diet to support normal growth AND the activity they are participating in.

Protein

Some sources state that intake of 20 grams of protein following vigorous exercise (such as after football practice) allow for maintenance of lean body mass/less loss of muscle.3 Protein supplements are not necessarily needed to re-supply the athlete with adequate protein intake.  Many times, a 16-ounce glass of chocolate milk provides an adequate amount of protein.3 Branched chain amino acids (BCAs) are advertised as a unique ingredient in these protein supplement drinks/bars, however many times these amino acids are present in whole foods such as egg whites.4 Increased levels of amino acids, such as leucine, can be detrimental to kidney function as well.  So, an increase in consumption of protein supplements may not be the best way to ingest enough protein to keep your athletic body running well.

Fats

Fats are the next most difficult substrate to monitor.  Protein and Carbohydrates carry 4 kilocalories (kCals) per gram, while fats carry 9 calories per gram.  Some sources state that an active OR sedentary individual should be consuming 25-30% of their total calories as fats.2 It is important to make sure the athlete is not over-consuming fats as a primary source of calories to prevent increases in body fat percentages, but too little fat consumption (less than 15%) may have negative health effects.1

Carbohydrates

Current research indicates that this area of nutrition is difficult to recommend for youth athletes.  This may be due to differences in utilization between adult athletes and youth athletes.  An athlete’s carbohydrate intake is recommended to be 50% of their total calorie intake.  That amount can be achieved by anywhere from 3 to 8 grams per kilogram of bodyweight.  Carbohydrate intake 30 minutes following vigorous competition or practice is important to replace carbohydrates stored in muscles.

 

Dietary Recommendations2

Fats: 20-25% of caloric intake, no less than 15%.

Protein: 0.8-1.2 g/kg of bodyweight sufficient to maintain body mass.  1.2-1.8 g/kg of body weight for athletes looking to increase lean body mass.6 Whole food proteins over synthetic protein supplements.

Carbohydrates: 50% of caloric intake, totaling 3-8g/kg of body weight.  1-1.5 g/kg of body weight post workout/practice.7

Water: 5-7 ml/kg of body weight 4 hours before competition. Water to replace fluid loss during competition greater than 2%.  450-675 ml for every .5 KG lost during exercise.  So, for a 100lb/45 kg athlete, they require 225-315 ml 4 hours before competition and enough water to replace anything over 2 lbs of body mass loss during competition.  They will need to be weighed after competition to determine amount of water to replace.


  1. American College of Sports Medicine. Joint Position Statement: nutrition and athletic performance.Medicine & Science in Sports & Exercise. 2000;32(12):2130–2145
  2. Smith JEW, Holmes ME, McAllister MJ. Nutritional Considerations for Performance in Young Athletes. J Sports Med. 2015:
  3. Murphy CH, Hector AJ, Phillips SM. Considerations for protein intake in managing weight loss in athletes.European J of Sport Sci. 2015;15(1):21–28.
  4. Elango R., Chapman K., Rafii M., Ball R. O., Pencharz P. B. Determination of the tolerable upper intake level of leucine in acute dietary studies in young men.The American Journal of Clinical Nutrition. 2012;96(4):759–767
  5. Smith J. W., Jeukendrup A. Performance nutrition for young athletes. In: Bagchi S. D. N., Sen C. K., editors.Nutrition and Enhanced Sports Performance: Muscle Building, Endurance, and Strength. Elsevier; 2013. pp. 523–529.
  6. Boisseau N., Vermorel M., Rance M., Duché P., Patureau-Mirand P. Protein requirements in male adolescent soccer players.European Journal of Applied Physiology. 2007;100(1):27–33
  7. Bonci L. Sports nutrition for young athletes. Pediatric Annals. 2010;39(5):300–306