Youth Athlete Development and Nutrition

TL;DR

This narrative review summarizes nutrition priorities for adolescent athletes (ages 13–18), emphasizing long-term health, adequate energy availability, and food-first macronutrient, micronutrient, and fluid guidance during growth and training. It warns that low energy availability, body-composition pressure, and supplement use can threaten health, and that many youth-specific sport-nutrition questions remain understudied.

Key findings

• The review’s key points advise that nutrition guidance for developing athletes prioritise long-term sustainable health and that the elite-performance pathway is complex and not dictated by undue emphasis on body composition. It notes that low energy availability (LEA) and potential relative energy deficiency in sport (RED-S) appear common in heavily training youth and can contribute to delayed puberty, menstrual irregularities, poor bone health, short stature, disordered eating, and increased injury risk; in females with a gynecological age of ≤ 14 years, LEA effects may be more pronounced.
• Energy needs vary widely: group estimates for adolescent athletes are ~3640 ± 830 kcal/day for males and ~3100 ± 720 kcal/day for females. A new resting metabolic rate equation from 126 junior athletes (mean age 16.5 years, range 13.1–19.7) is RMR (kcal/day) = 11.1 × body mass (kg) + 8.4 × height (cm) − (340 male or 537 female); adult-based equations may underestimate energy expenditure by up to 300 kcal/day. Protein needs during peak growth include lean-mass gains of ~2.3 g/day in females and ~3.8 g/day in males (~threefold prepubertal); ~0.11 g/kg/h post-exercise or ~1.5 g/kg/day (e.g., ~0.3 g/kg × 5 meals) should suffice with adequate energy. For carbohydrate, a single source (glucose) can be oxidised at up to ~0.6 g/kg/h in young boys, so a 45 kg 12-year-old could use ~30 g CHO/h. Dietary fat guidance is 20–35% of total energy, with saturated/trans fatty acids ≤10%.
• Iron depletion is frequently observed in adolescent athletes; the paper’s table defines stages by serum ferritin <35, <20, and <12 µg/L with haemoglobin/transferrin saturation criteria. Calcium accretion during adolescence is estimated at ~300 mg/day, and recommendations range from 800 to 1300 mg/day. Vitamin D recommendations differ by region: Australia 5 µg/day, US/Canada 15 µg/day, Europe 10–20 µg/day. Trained adolescent athletes can show fluid deficits >4% body weight and sweat rates ≤2.16 L/h; advised fluid intake is ~13 mL/kg per hour of exercise, with body-mass losses limited to ≤2% from pre-exercise values.
• Performance-enhancing supplement use among US children and adolescents (<18 years) was 1.6%. Most products lack rigorous effectiveness and long-term safety evidence in younger populations, and the review states that legal supplements typically offer only 2–5% improvement, over-emphasizing their ability to manipulate performance. It concludes that nutrient needs should be met by food rather than supplements, except for clinical use under qualified guidance.

Methods

• The paper describes itself as a narrative review incorporating physiology, psychology, training science, and sociology to describe current understanding of nutrition priorities for developing adolescent athletes.
• No primary data collection, systematic review protocol, or meta-analysis is reported; evidence is synthesized from published literature, position statements, consensus guidelines, and reference values.
• Several cited numbers come from other studies (e.g., n = 126 RMR cohort; >70 adolescent female athletes; US supplement prevalence 1.6%), but these are secondary citations rather than new analyses.

Limitations

• The paper states many evidence gaps: no specific calcium recommendations for athletes; unclear influence of vitamin D status and benefits of supplementation in deficient youth athletes; no evidence on whether fluid intake modulates heat-illness risk in adolescent athletes; no studies of centrally mediated carbohydrate effects in adolescents; and limited rigorous effectiveness/long-term safety data for supplements in younger populations.
• Evident from the text: as a narrative review, it lacks a systematic search or selection strategy, so coverage and conclusions may reflect the author’s synthesis rather than exhaustive evidence; several recommendations are extrapolated from adult data or population guidelines because youth-specific data are absent.