Diets, Teenages, nutrition | July 9, 2017 | Author: Naturopath
In Australia, approximately 60 percent of children aged 5-14 years participate in at least one sport outside of school hours that had been organised by a school, club or association.
These young athletes need to consider adequate nutrition not only for their athletic performance, but also and more importantly for achieving their full growth and development potential, and for overall health
Peak athletic performance requires sufficient energy (kilojoules) intake. The main sources of energy in the diet are carbohydrates, proteins, and fats. They are required for adolescent athletes in different amounts, depending on age, growth rate, and activity level – frequency, duration, and intensity.
Carbohydrates. Carbohydrates are the main energy source, providing readily available fuel in the form of glucose, which is stored as glycogen in muscles and liver. They are especially essential during prolonged continuous or high-intensity exercise. As you exercise, your muscles release the stored glycogen. Inadequate intake of carbohydrates may result in fatigue and a decline in immune system function.
Good sources of carbohydrates include whole grains, vegetables, fruits, milk and yogurt. Pastries, cakes, hot chips, crisps, and chocolate are sources of carbohydrates too, but are high in fat and are not recommended.
Protein. Protein is necessary for building and repairing muscle after exercise, and as such is often required more by endurance athletes in heavy training, rather than for mild or short-duration exercise. Protein is also used as a marginal energy source when carbohydrate reserves are low.
Good sources of protein include lean meat and poultry, fish, legumes (dry beans and peas), tofu, eggs, nuts and seeds, milk and milk products (cheese and yogurt).
Fat. Fat is an essential component part of a healthy diet. Nutrition Australia states that fat is the main energy source for long duration events such as marathons, and that moderate amounts of healthy fats should be included in the diet of any athlete. These include lean meat and poultry, fish, nuts, seeds, dairy products, and olive oil and avocado. Fat from chips, fried foods and baked goods such as pastries should be avoided or limited.
Iron. Iron is important for carrying oxygen to body tissues, including muscles, for producing red blood cells, and for a healthy immune system. Adolescents require iron during growth and development to provide for the increase in blood volume and muscle mass. Young athletes - in particularly female athletes, vegetarians and distance runners - may suffer a deficiency due to poor diet or increased iron losses in urine, faeces, sweat, menstrual blood or sport injury.
Good sources of iron include lean meats and fish, eggs, beans, leafy green vegetables, and fortified whole grains.
Calcium. Calcium is important for bone health and muscle contraction, and to reduce the risk of osteoporosis in later years. About 45% of the adult skeletal mass is attained during adolescence; thus, adequate calcium intake is crucial. Furthermore, adolescent athletes are more susceptible to injuries from repetitive stress because their growing bones cannot handle as much stress as an adult’s mature bones.
According to Sports Dietitians Australia Position Statement, “Calcium requirements for adolescent athletes are no different from that of non-active adolescents; however, requirements are greater than that of adults due to growth.”
Good sources of calcium include milk, cheese and yoghurt. Non-dairy foods that are good sources of calcium include sardines and salmon (with bones), broccoli, nuts and seeds, and products fortified with calcium such as breakfast cereals, and soy beverages.
Vitamin D. Vitamin D plays a role in development and maintenance of bone health, by promoting absorption of calcium and phosphate. Studies suggest that vitamin D status is associated with injury prevention and rehabilitation. Young athletes who primarily train and compete indoors are likely at higher risk for vitamin D insufficiency.
Water is an important nutrient for all athletes, essential for regulating body temperature and replacing fluids losses through sweat during exercise. As children and adolescents are less efficient than adults in regulating body temperature, they should be properly hydrated. Dehydration is associated with fatigue, impaired performance, and increase the risk of heat exhaustion or heat stroke. Fluid intake is required before, during and after exercise.
What drink? The Australian Institute of Sport recommends drinking water immediately before exercise sessions commence, and continue to drink small amounts regularly.
Sports drinks are a suitable option too, especially when fluid losses are high and/or rapid rehydration, as they replace sodium loss. Research shows sports drinks stimulate and improve fluid intake. Coconut water is another option but soft drinks, cordial and fruit juices are not!.
Pre-exercise. The purpose of eating before the exercise is to provide fuel and fluids; however, eating just before you exercise, especially large quantities before high intensity sports may cause stomach discomfort. Again, this depends on the type, duration and intensity of the exercise. A general rule by the Australian Institute of Sport is to have a meal about 3-4 hours before exercise or a lighter snack about 1-2 hours before exercise. Pre-exercise food should include carbohydrates, moderate protein, and should be low in fat and fibre as they are slow to digest.
Post exercise. Recovery food and fluid post exercise is necessary for replenishing glycogen stores, rehydration, building and repairing muscle and red blood cells. The Australian Institute of Sport recommends consuming a carbohydrate rich snack or meal that provides 1-1.2 g of carbohydrate per kg body weight within the first hour of finishing. The post recovery meal or snack should include some protein too.
Real food is the best option for young athletes; there is no need for special sport supplements. However, deficiencies of iron, calcium or vitamin D may need supplementation.
American College of Sports medicine 2016, Nutrition and Athletic Performance, ACSM. Medicine & Science in Sports & Exercise, 48(3), 543–568.
Australian Bureau of Statistics 2012, Sports and Physical Recreation: A Statistical Overview, Australia, 2012 - Children’s participation. ABS, retrieved
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Desbrow, B., McCormack, J., Burke, et al. (2014). Sports Dietitians Australia Position Statement: Sports Nutrition for the Adolescent Athlete. International Journal of Sport Nutrition and Exercise Metabolism, 24(5), 570–584.
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