Nutrition Strategies for Elite Swimmers During the Training Phase

Gabriela Schmidt
2025-10-16T13:21:00+01:00

Key Takeaways

Carbohydrates drive performance: Periodise intake based on training load (8–10 g/kg on heavy days).

Protein supports repair: Aim for 20–30 g every 3–4 hours, plus casein before bed.

Whey protein is recovery gold: Fast-digesting, leucine-rich, and convenient for hitting higher daily protein targets.

Hydration is vital: Sweat losses occur even in the pool—replace fluids and electrolytes.

Micronutrients matter: Iron, vitamin D, and omega-3s help maintain health and performance.

Dr. Crionna Tobin (Head of Nutrition, Optimum Nutrition): Ju Liang, swimmers are some of the hardest training athletes in the world. They can clock up five to seven hours of training a day in the pool and gym. That’s a huge energy demand. How do you approach fuelling athletes at this level during the training phase?

Yu Liang (Head Nutritionist, Chinese Olympic Team): You’re right, Crionna. The training load for elite swimmers is extraordinary. The foundation of our approach is ensuring energy availability. If energy intake doesn’t match expenditure, we risk under-fuelling, which can compromise recovery, immune function, and adaptation. So, carbohydrates become central—both in quantity and timing. We encourage swimmers to consume carbohydrate-rich meals before and after key training sessions to maximise glycogen availability and replenish stores quickly.

Dr. Crionna Tobin: Absolutely. Carbohydrates are often misunderstood. For endurance-heavy athletes like swimmers, they’re not just fuel but a signal to the body that energy is available. Without sufficient carbohydrate, intensity drops. At Optimum Nutrition, we often talk about matching carbohydrate intake to training intensity—higher on double-session days, lower when training load eases. Do you do the same?

Yu Liang: Yes, carbohydrate periodisation is very effective. On heavy days, swimmers may consume 8–10 g per kilogram of body weight. On lighter days, that can reduce. But protein is just as important—spread across the day, around 20–30 g every three to four hours, including after every swim and gym session. That supports muscle repair and lean mass maintenance, which are critical for powerful strokes in the water.

Dr. Crionna Tobin: I couldn’t agree more. I often explain to athletes that protein isn’t just about size; it’s about function—repair, recovery, and overall wellness.

Yu Liang: And let’s not forget whey protein. We use it a lot with swimmers because it’s a convenient and effective way to boost protein intake. Whey is rapidly digested and rich in leucine, the key amino acid that stimulates muscle protein synthesis. After a tough training session, a shake with 25–30 g of whey protein helps kick-start recovery.

Dr. Crionna Tobin: Exactly. Convenience matters when athletes are training multiple times a day. They don’t always have time for full meals between sessions. Whey protein allows them to hit higher daily protein numbers without feeling overly full, which can be a challenge given their huge energy demands. It’s a high-quality solution that fits seamlessly into the training environment.

Yu Liang: Another area we focus on is hydration. Training in water can mask sweat losses, but swimmers can lose significant fluid and electrolytes. We monitor body mass before and after sessions and encourage fluid intake with electrolytes, particularly sodium, to maintain balance.

Dr. Crionna Tobin: That’s such a good point. Many swimmers underestimate hydration needs because they don’t “feel” sweaty in the pool. But even mild dehydration can reduce performance and delay recovery. Beyond the macronutrients, what about micronutrients?

Yu Liang: Iron and vitamin D are priorities. Iron supports oxygen transport, which is vital in aerobic-heavy sports like swimming. Vitamin D is important for bone health and muscle function, and deficiency can be common, especially in athletes training indoors or in regions with low sun exposure.

Dr. Crionna Tobin: Yes, in the UK and Europe we see the same issues. Omega-3 fatty acids are also useful and of course, supplements like creatine can be beneficial, provided they’re third-party tested.

Yu Liang: Creatine is interesting. Many people think it’s only for strength athletes, but research shows it can help swimmers improve repeated sprint ability and support recovery.

Dr. Crionna Tobin: Exactly. So, to summarise: elite swimmers in training need a balance of energy, carbohydrate periodisation, consistent protein intake, high-quality whey for recovery, good hydration, and targeted micronutrients. That combination helps them recover, adapt, and perform at their very best when it matters.

References

Burke LM, Hawley JA. 2018, Swifter, higher, stronger: What’s on the menu? Science.

Morton RW, et al., 2018. Protein supplementation to support adaptations to resistance training: a systematic review and meta-analysis. Br J Sports Med.

Phillips SM. 2014, A brief review of higher dietary protein diets in weight loss: a focus on athletes. Sports Med.

Kreider RB, et al. 2017,International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation. J Int Soc Sports Nutr.

Thomas DT, Erdman KA, Burke LM. 2016, 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.

Meet the Experts Behind This Conversation

Yu Liang

Chief Nutritionist for the Chinese National Swim Team, is a leading sports nutritionist whose work helped athletes win 3 gold medals and set world records at the 2024 Paris Olympics. He is also dedicated to making elite nutrition accessible to the public.

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Dr. Crionna Tobin, PhD

Provides guidance on sports and active nutrition to athletes, internal teams and brand partners in her role as Head of Science and Education at Optimum Nutrition. Her deep expertise is backed by a PhD in performance nutrition and exercise physiology from Dublin City University.