The prospect of sporting success is appealing to many young athletes and their families. Organised sport provides several benefits to young people, including regular physical activity, social interaction and the development of confidence and self-esteem. Indeed, a commitment to regular physical activity is promoted in population dietary guidelines, regardless of age. While population dietary guidelines and nutrient reference values are appropriate for addressing the micronutrient and energy requirements of children and adolescents involved in most sports, those involved in high-intensity sports training programs have higher nutrient and energy requirements. The basic principles of sports nutrition recommended to adult athletes also apply to younger athletes.
Meeting higher nutrient and energy requirements during periods of rapid growth, while also coping with changing body composition and metabolic and hormonal fluctuations, is often challenging for young athletes. Social and emotional factors, stage of development and maturational timing has a major influence on how individuals view themselves and their sporting achievements. Childhood and adolescence is a critical time in life to develop long-term food habits and the connections between food, exercise and body image. New practices, beliefs and meanings associated with food may be acquired during this time, such as the adoption of vegetarianism, fad diets and supplement use. It is also important to recognise that athletic performance development is non-linear, with success at junior competitions not always translating to success as an adult. Hence, it is important that young athletes develop eating patterns that integrate the unique requirements for sporting success and ensure healthy growth and development. Furthermore, contemporary physical activity guidelines for children and adolescents recognise that sleep, sedentary behaviour and physical activity are behaviours that should not be considered in isolation. Referred to as 24-hour integrated movement guidelines, these guidelines acknowledge that the whole day matters and individual movement behaviours (e.g. physical activity, sedentary behaviour, sleep) need to be considered in relation to each other when examining their associations with health and developmental outcomes in children (AGDoH 2019). It is important to also consider the nutrition needs of physically active children and adolescents in this context.
This chapter considers how the physiological response to exercise and the nutritional requirements of children and adolescents participating in sport may differ from adult athletes. Identifying body composition changes during growth, development and maturation is crucial to advising young athletes about expected changes in body composition, nutrient requirements and response to exercise.
In this chapter, children refers to those aged 5–12 years, and adolescents to those aged 13–18 years, according to population categories (NHMRC 2013).
GROWTH AND DEVELOPMENTAL CHANGES IN THE YOUNG ATHLETE
Growth is divided into three additive components: infancy, childhood and puberty (Karlberg 1989a, 1989b, 1990). Identifying stage of growth and development and changes to body composition during maturation of young athletes is fundamental for the sports dietitian to estimate nutrient requirements and advise ...