ENERGY AVAILABILITY AND RED‑S IN YOUTH ATHLETES

Why Energy Availability Matters for Youth Athletes

 

Energy availability (EA) is the energy left for growth, development, and normal physiological function after subtracting the energy used for training.

For youth athletes, EA is a developmental requirement.

 

Low energy availability (LEA) affects:

• growth

• bone development

• hormonal maturation

• cognitive function

• immune health

• injury risk

• training tolerance

• emotional regulation.

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Many junior athletes unintentionally fall into LEA due to:

• high training loads

• skipped meals

• inadequate carbohydrate intake

• fear of weight gain

• restrictive eating patterns

• misunderstanding of nutrition needs.

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LEA is the foundation of RED‑S (Relative Energy Deficiency in Sport), which disrupts multiple body systems (Alcock, 2025; Amawi, 2024a; Capra, 2024; Desbrow, 2021; Hecht, 2024; Everett, 2025).

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Youth‑Specific Physiology and Energy Needs

 

Youth athletes must fuel:

• growth

• training

• daily life and cognitive development.

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Growth Requires High Baseline Energy

Energy is required for:

• bone formation

• muscle development

• hormonal maturation

• organ growth

If intake is insufficient, the body prioritises survival over growth or performance.

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Training Adds a Second Energy Demand

Youth athletes often train:

• daily

• multiple times per day

• across multiple sports

This significantly increases total energy expenditure.

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Cognitive Development Requires Glucose

The developing brain consumes a large portion of daily energy. Low carbohydrate availability impairs:

• focus

• reaction time

• learning

• emotional stability.

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Youth Have Limited Energy Reserves

Compared to adults, youth have:

• lower glycogen storage

• higher metabolic heat production

• faster nutrient turnover

This increases LEA risk when intake is inconsistent (Capra, 2025; Desbrow, 2021; Everett, 2025; Hecht, 2024).

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What Is RED‑S?

 

RED‑S occurs when chronic low energy availability disrupts:

• growth

• bone health

• menstrual function

• metabolic rate

• immunity

• cardiovascular function

• psychological health

• training adaptation.

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In youth, RED‑S can:

• delay puberty

• impair peak bone mass development

• increase injury risk

• reduce long‑term athletic potential

(Alcock, 2025; Everett, 2025; Hecht, 2024).

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Signs and Symptoms of Low Energy Availability in Youth

 

Physical Signs

• fatigue

• frequent injuries

• stress fractures

• poor recovery

• dizziness

• cold intolerance

• slowed growth

• menstrual irregularities (females).

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Performance Signs

• reduced endurance

• decreased strength

• slower reaction time

• inconsistent performance

• early fatigue in training.

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Behavioural Signs

• skipping meals

• fear of certain foods

• rigid eating patterns

• excessive training

• preoccupation with weight

(Amawi, 2024a; Everett, 2025).

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LEA, Bone Health, and Injury Risk

Bone development peaks during adolescence. LEA disrupts:

• bone formation

• calcium metabolism

• vitamin D utilisation

• hormonal regulation.

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This increases risk for:

• stress fractures

• delayed skeletal development

• long‑term bone weakness

(Alcock, 2025; Capra, 2024).

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LEA and Eating Disorder Risk

Youth athletes with LEA often show:

• restrictive eating

• meal skipping

• dehydration behaviours

• fear of weight gain

• pressure from sport environments.

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These patterns increase risk for:

• disordered eating

• RED‑S

• psychological distress

• impaired development

Early identification is essential (Amawi, 2024a).

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Practical Energy Availability Strategies 

 

Daily Structure

• eat every 3–4 hours

• include carbohydrates at each meal

• include protein at each meal

• include healthy fats daily

• avoid training on an empty stomach.

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Training Day Strategies

• pre‑training snack

• carbohydrate during long sessions

• post‑training recovery meal

• increased intake on double‑session days.

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Monitoring Growth and Recovery

• track growth patterns

• monitor menstrual function (females)

• watch for fatigue or mood changes

• monitor injury frequency.

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When to Seek Professional Support

• recurrent injuries

• rapid weight loss

• menstrual irregularities

• persistent fatigue

• restrictive eating behaviours

(Alcock, 2025; Amawi, 2024a; Capra, 2024; Everett, 2025; Hecht, 2024).

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Youth‑Friendly Explanation

 

Why Energy Matters

Energy helps you:

• grow

• train hard

• stay healthy

• recover fast

• think clearly.

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What Works

• eating enough

• fuelling before training

• refuelling after training

• eating carbs, protein, and fats.

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What Doesn’t Work

• skipping meals

• eating too little

• cutting out food groups

• training without fuel.