Children who participate in high-level sports need a diet that will support this intense training. Insufficient energy and nutrient intakes may cause growth and maturation may be delayed.
A healthy child’s diet should provide adequate energy and nutrients to support normal growth as well as the increased energy needs for training.
Children’s dietary needs differ from those of adults. Fluid, for example, is a specific challenge for children as they do not tolerate extreme temperatures well and produce less sweat. When they reach adolescence, children are faced with additional challenges that include sexual maturation, change in body compositions, rapid growth, coach, parent and peer pressure, scholastic achievement and social acceptance.
During puberty, girls gain more body fat than boys (due to the laying down of energy for pregnancy and lactation), whereas boys gain twice as much muscle mass. This causes distress among many teenage girls, resulting in distorted body images, dieting and, in some cases, the development of eating disorders. Boys, on the other hand, want to look more masculine and may use nutritional supplements to achieve this.
It is thus crucial that parents, coaches and sports physicians co-operate in monitoring the child’s development to detect problems early on and to establish lifelong healthy eating patterns.
The energy needs of healthy, growing children vary depending on their age, physical activity level and sex. It is thus crucial that a child’s needs be worked out on a individual basis.
Adult values should also not be used, as they may underestimate the energy requirements of children who are less metabolically and mechanically efficient, therefore needing more energy for their weight and height. Children also need more energy and growth for maturation. The estimated Energy Requirements (EER) and Physical Activity Levels (PAL) can be used as broad guidelines.
Protein requirements are increased during childhood and adolescence to support growth and the additional demands of exercise and developing muscle mass. Children and adolescents require more protein than adults because of the extra protein required for growth. Protein is also required for gains in lean body mass and to compensate for muscle regeneration.
However, there is a limit to the amount of protein than the muscle can use. It is also important to have sufficient carbohydrate together with the protein, because it provides the necessary energy to fuel the work that the muscle to stimulate it to grow.
Protein intake should make up to 15-20% of the total energy consumed and to up to 2g/kg body weight in male teenage athletes. Children likely to be at risk for inadequate protein intake include strict vegetarians or vegans, children with multiple food allergies or those who have limited access to food, or who follow very high carbohydrate diets.
Vitamin and mineral supplementation should not be necessary if the child meets the higher requirements and consumes a varied diet with nutrient-dense food choices. Iron, calcium and zinc intake is of great importance, especially during periods of rapid growth.
An iron deficiency can follow periods of rapid growth, impacting negatively on sporting performance. In boys the gain is muscle mass is accompanied by an increase in blood volume and in girls iron is lost monthly due to menstruation. Adolescents who restrict their food intake because they think they are fat, often suffer from iron-deficiency anaemia.
Calcium requirements increase substantially during adolescence to meet the demands of bone growth and to achieve a good bone mass.
Zinc is also essential to growth, but the retention of zinc increases during growth spurts, leading to more efficient use of dietary sources.
Children older than two should have a daily fibre intake equal to their age plus 5g. Good sources of fibre include high-fibre cereals, wholegrain breads and crackers, oats porridge, legumes, fruit and vegetables.
Drinking is important to replace fluid losses and young athletes often begin training after school, when they are already dehydrated. Fluids can also provide energy in the form of carbohydrates. Sports drinks provide both carbohydrates and fluid, but so does fruit juice (preferably diluted by 50%), diluted cordial or a carbohydrate powder added to water.
When energy and nutrient intakes are insufficient in teenage girls, menarche (onset of menstruation) may be delayed. This might lead to menstrual dysfunction, resulting in low peak bone density. This is of great concern in aesthetic sport like gymnastics and ballet, where young athletes often severely restrict their energy intake to achieve lower body weights.
In boys and girls total catch-up growth may be compromised if the delay in maturation is severe. In addition, immature bones are more susceptible to stress injuries.
Instead of cutting calorie intake, parents might want to look at better snack choices and decreasing time spent watching TV. There is a very close correlation between the time spent watching TV and weight gain. Not only is this inactive time, but the advertising of fast foods and inappropriate snacks encourages poor food choices.
Tooth decay is accelerated by two conditions: sticky carbohydrates that stick to tooth surfaces for a long time; and frequent exposure of tooth surface to sugar. Therefore, sticky sweets are more likely to be harmful than a sports drink, because, while providing the same amount of sugar, the drink is less likely to stick to the teeth for long. If eating or drinking sugary foods and beverages between meals, it is important to brush, floss and rinse the mouth afterward.