Swimming nutrition for pool and open-water swimmers

At a glance

• Training pattern: Early mornings, often twice daily
• Competition format: Heats, semi-finals and finals
• Fuelling challenge: Fitting food around pool times
• Health watch: Low energy availability and body image

The demands of swimming

Competitive swimming is built on high training volume. Squads often train before work or study and again in the evening, alongside land-based strength sessions. Pool races are short, from sprints lasting well under a minute to distance events, but the training behind them is long. The result is high energy needs packed around awkward times, with little chance to eat during the sessions themselves.

Competition is organised into heats, semi-finals and finals, often split across morning and evening sessions and over several days. Swimmers need to recover quickly between swims, eat enough without feeling heavy, and manage long waits on poolside. Sprinters rely on power and the ability to repeat maximal efforts, while distance swimmers need a stronger aerobic fuel base to sustain the work.

Open-water swimming adds cold or warm water, waves, currents and long durations, with feeding only at set points from a pontoon or support boat. Swimmers rarely notice sweating, yet still lose fluid, and cold water raises energy cost. In a sport where bodies are highly visible on poolside, some swimmers also become vulnerable to restricting food, which raises the risk of RED-S.

Nutrition priorities for swimmers

Fuel early-morning sessions

A small, easily digested carbohydrate snack before dawn sessions, followed by a proper breakfast, helps protect training quality. We plan this around your squad timetable.

Match carbohydrate to pool volume

Swimmers training 1–3 h a day typically need 6–10 g/kg/day of carbohydrate, with needs at the lower end on lighter or technique-focused days. [1]

Recover between double sessions

With only hours between sessions, 1.0–1.2 g/kg/h of carbohydrate for the first 4 h after the morning swim helps you get more from the evening session. [1]

Spread protein for pool and gym

About 0.3 g/kg of high-quality protein after sessions and at regular meals supports adaptation from both swimming and strength work. [1]

Fuel long open-water swims

For swims of 1–2.5 h, 30–60 g/h of carbohydrate is a useful guide, taken at feeding points as drinks or gels you have practised with. [1]

Watch for low energy availability

High volume, early starts and body-image pressure make RED-S a risk in swimming. We screen for warning signs and work with your wider support team. [2]

Gala and competition-day fuelling

1. Day before: Keep carbohydrate intake steady with familiar meals, and pack snacks and drinks for poolside so you are not relying on venue food.
2. Before your first swim: Eat a familiar carbohydrate-based breakfast a few hours before warm-up, adjusting the amount to how early your first heat is and how your stomach copes.
3. Between heats and finals: Use small, regular carbohydrate snacks and fluids during long waits, and have a proper meal between morning heats and evening finals.
4. After your last swim: Have carbohydrate and about 0.3 g/kg protein soon after, especially if you are racing again the next day of a multi-day meet. [1]

General guidance from sports nutrition consensus statements. Your practitioner will tailor amounts to you.

Events and their demands

Sprint swimmers

Short, maximal races and gym work make power, protein spread and recovery between rounds the priorities.

Middle and distance swimmers

Higher aerobic training volume raises daily carbohydrate needs and the importance of recovery between sessions.

Open-water swimmers

Long swims with fixed feeding points need practised drinks or gels, plus attention to cold, heat and fluid losses.

Masters swimmers

Usually training around work, so fuelling early sessions and maintaining muscle and bone health matter most.

What we help with

• Training before breakfast and struggling for energy
• Not eating enough between heats and finals
• Tiredness and illness through high-volume training blocks
• Body-image pressure in a sport where bodies are visible
• Planning feeds for long open-water swims
• Building strength alongside heavy pool volume

Ongoing support, not one-off sessions

We do not work with athletes on a one-off basis. Sports nutrition works best when it adapts to your training, so we recommend an initial consultation followed by at least three follow-ups.

Who you could work with

• Jenaed Ruddock, HCPC-registered Sports Dietitian (SENr)
• Beatriz Ribeiro, HCPC-registered Dietitian
• Melissa Bosch, Eating Disorder Nutrition Specialist

Book your consultation

Book an initial consultation or book a free discovery call to talk it through first. All consultations are online.

Explore more

See all the sports we work with, our RED-S nutrition support, or meet the team.

Frequently asked questions

What should a swimmer eat before early-morning training?

Something small and easy to digest, such as toast, a banana or a yoghurt, is often better tolerated than nothing at all, particularly before harder sets. A proper breakfast afterwards matters just as much. We find options that suit your stomach and your timetable.

How should I eat between heats and finals?

If the gap is short, small carbohydrate snacks and fluids keep you topped up without feeling heavy. With several hours between morning heats and evening finals, a proper meal, rest and a light snack before warm-up usually works well. We create a plan around your meet schedule.

Do swimmers need to drink during training?

Yes. Swimmers still sweat in the pool, especially in warm pools and hard sessions, even though it is hard to notice. Keeping a bottle at the end of the lane helps, and we can estimate your losses by weighing before and after sessions.

Can you help with body-image worries in swimming?

Yes. Our team includes RED-S specialists and an Eating Disorder Nutrition Specialist who supports athletes with under-fuelling and disordered eating. Where needed, we work alongside psychologists, GPs and specialist services rather than replacing them.

How many consultations will I need?

We do not work with athletes on a one-off basis. Swimming plans need adjusting as training volume shifts through the season and around galas, so we recommend a minimum of three follow-up consultations after your initial consultation.

Do you work with junior swimmers?

Many competitive swimmers are teenagers. These pages are for adult swimmers, and young swimmers are supported through our paediatric team.

References

1. Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet. 2016;116(3):501–528.
2. Mountjoy M, et al. 2023 International Olympic Committee (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). Br J Sports Med. 2023;57(17):1073–1097.