Nutrition For Young Swimmers (Aged 11 - 18)

Good nutrition is an essential part of swim training. Eating the right foods - in the right amounts and at the right times - helps swimmers train harder, recover faster, and stay healthy throughout the season.

For parents and coaches, supporting good eating habits is as important as supporting good technique. Young swimmers are growing fast and training hard, often for hours a day, so their bodies need plenty of fuel to perform, recover and develop properly.

The energy demands of swim training

Competitive swimmers often train two to four hours a day, sometimes in double sessions. Add school, growth and recovery, and energy needs can be double those of less active teenagers.

Energy from food powers:

  • Training and competition

  • Growth and development (bones, muscles, hormones)

  • Recovery and adaptation

  • Concentration and learning

  • Immune function

When swimmers don’t eat enough to meet these demands, the body starts to conserve energy. Growth may slow, fatigue can set in, and performance often declines. This is known as low energy availability (LEA) and, if it continues, can lead to Relative Energy Deficiency in Sport (RED-S), a condition that affects both health and performance.

Why fuelling properly matters

Under-fuelling can happen easily - skipping breakfast, eating too little after training, or cutting down on carbohydrates. Even small energy gaps, repeated over time, can lead to problems.

Warning signs of RED-S or low energy availability include:

  • Persistent tiredness or lack of energy during training

  • Declining performance despite consistent effort

  • Frequent illness or injury

  • Difficulty sleeping

  • Mood changes, irritability or low motivation

  • Missed or irregular periods in girls

  • Stalled growth or muscle loss

If these occur, it’s important to seek advice from a doctor or registered sports nutritionist.

Eating enough, and eating regularly, helps swimmers stay strong, recover faster and maintain health. Fuel is your friend, not your enemy.

Building a healthy swimmer’s plate

A balanced diet provides carbohydrates for energy, protein for growth and repair, healthy fats for hormone and heart health, and a variety of vitamins and minerals for overall wellbeing.

A simple way to build meals is to divide the plate into thirds:

  • ⅓ carbohydrates – pasta, rice, bread, potatoes, oats, cereals

  • ⅓ protein – chicken, fish, eggs, lean meat, tofu, beans or lentils

  • ⅓ vegetables or salad

Add healthy fats such as olive oil, nuts, seeds, avocado or oily fish, and aim for at least five portions of fruit and vegetables each day.

On heavy training days, slightly increase the carbohydrate portion to match the extra energy demand.

Before early morning training

Many swimmers train early, when appetite is low. But swimming on an empty stomach can lead to low blood sugar, early fatigue and poor concentration.

A small, high-carbohydrate snack before training provides valuable fuel. Suitable options include:

  • Toast with honey or jam

  • A banana or other fruit

  • A cereal or fruit bar (e.g. Nakd, Eat Natural)

  • Porridge made with milk or a milk alternative

  • A smoothie made with fruit and milk

If solid food isn’t appealing, a drink that provides energy, such as a fruit smoothie or diluted fruit juice, is a good alternative. It also helps to have a glass of water before leaving home to rehydrate after sleep.

After morning training

After training, muscles need carbohydrate and protein to refuel and repair. Aim to eat within 30–60 minutes of finishing your session.

Good post-swim breakfasts include:

  • Porridge made with milk, topped with banana, berries and a handful of nuts or seeds

  • Wholegrain toast or bagel with eggs, plus fruit on the side

  • Greek yogurt with granola and fruit

  • Smoothie made with milk, oats and fruit

  • Wholegrain cereal with milk and sliced banana

These meals replace energy stores, support muscle recovery and prepare you for the day ahead.

Eating through the day

Regular eating helps swimmers maintain energy and concentration. Skipping meals leads to tiredness, poor focus and reduced training quality.

A good pattern is three main meals and two to four snacks each day.
Snacks for school or between sessions might include:

  • Fresh or dried fruit

  • Yogurt or milk drink

  • Sandwich, wrap or roll

  • Nuts, seeds or a cereal bar

  • Crackers with cheese or peanut butter

Eating consistently throughout the day supports steady energy levels and healthy growth.

Fuel before evening training

The main pre-training meal should be eaten two to three hours before swimming, giving enough time for digestion.

If training starts at 7 pm, eat around 4–5 pm; if earlier, have a lighter meal or snack at 3–4 pm.

Good pre-training meals include:

  • Pasta with tomato sauce and chicken, fish or tofu

  • Rice with beans, salmon or lean meat plus vegetables

  • Jacket potato with tuna, cheese or beans

If time is short, a smaller snack 30–60 minutes before training will help maintain energy:

  • Toast with jam

  • Banana and yogurt

  • Dried fruit and nuts

  • Cereal with milk

During training: stay hydrated

Even in the pool, swimmers sweat and lose fluid. Dehydration makes training feel harder and reduces performance.

To stay hydrated:

  • Begin sessions well hydrated - urine should be pale yellow

  • Sip small amounts regularly (around 125–200 ml every 15–20 minutes)

  • For long or intense sessions, use a diluted squash (1:6 ratio) or light sports drink to replace both fluid and carbohydrate

  • After training, rehydrate with water, milk or a recovery drink

Recovery after training: the 4 Rs

Recovery is when the body adapts to training - muscles repair, energy stores refill and strength improves. Because sessions are often just hours apart, effective recovery is crucial for young swimmers.

Think of the 4 Rs:

1. Refuel – replace energy stores

Carbohydrate is the body’s main training fuel. Replenish glycogen as soon as possible - ideally within 30 minutes of finishing.

  • Aim for about 1 g carbohydrate per kg body weight (e.g. 50 g for a 50 kg swimmer).

  • Easy options include banana and yogurt, a smoothie, porridge, or a sandwich.

2. Repair – rebuild muscles

Protein supports recovery and growth.

  • Aim for about 0.3 g protein per kg body weight (15–25 g for most teens).

  • Good sources include milk, yogurt, eggs, chicken, fish, tofu, beans or lentils.

  • Spread protein evenly across meals and snacks for best results.

3. Rehydrate – replace fluids and electrolytes

Even in the pool, fluid losses can be significant.

  • Replace around 1.5 litres of fluid for every kilogram of body weight lost during training.

  • Milk or flavoured milk are ideal as they provide fluid, electrolytes, carbohydrate and protein together.

4. Rest – allow time to adapt

Nutrition jump-starts recovery, but rest and sleep complete it.

  • Aim for 8–10 hours of sleep each night

  • Short naps or quiet breaks between sessions also help

Good recovery options:

  • 500 ml milk, chocolate milk or milkshake

  • Smoothie with milk or yogurt, fruit and oats

  • Greek yogurt with berries and granola

  • Wholegrain toast or sandwich with peanut butter, cheese or chicken

Then, have a balanced meal — including carbohydrates, protein and vegetables — once you get home.

Supporting growth and long-term health

Swimmers aged 11–18 are still growing, so nutrition must support both performance and development. Under-eating can affect growth, bone health and hormones.

Parents and coaches should encourage balanced, consistent eating rather than restriction. Emphasise wellbeing and performance, not weight.

Iron is especially important for teenage girls. Include lean red meat, beans, lentils, leafy greens and fortified cereals, and pair them with vitamin C-rich foods to boost absorption.

Supplements are rarely needed if the diet is varied and balanced. If used, always choose Informed-Sport certified products.

Key take-home tips

  • Fuel every session – carbohydrates are your main energy source

  • Eat regularly – three meals and snacks to meet daily energy needs

  • Recover smart – carbs, protein, fluids and rest after each session

  • Stay hydrated – before, during and after swimming

  • Watch for warning signs – fatigue, poor recovery or missed periods can signal under-fuelling

  • Focus on performance, not restriction – your body needs fuel to swim fast and grow strong

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