What to eat
Everybody is built differently and so some of the advice given below may not be appropriate for everybody.
This information is for general guidance only, for personalised advice please speak to a specialist dietician or other appropriate medical professional.
Because swimmers burn a lot of energy, they should take in more carbohydrate than normal. Carbohydrates should form as much as 60% (i.e. the bulk) of their diet, at the expense of fat.
Carbohydrate fuels: starch v sugar
Starches (‘slow burn’)
Because swimming is an endurance activity, the energy release from foods needs to be gradual. Starches are ‘slow burn’ energy sources and should form the bulk of the diet
Sugars ('fast burn')
Sugars such as fructose and glucose are converted almost instantly to energy. They are therefore only useful in certain circumstances, i.e. immediately prior to exercise and to replenish energy reserves after a training session. If not used, sugars are converted to fat. They can also inhibit re-hydration.
When to eat
Swimmers must also eat small amounts periodically (every half hour or so) during competitions to maintain the energy store. When this runs out, a swimmer's performance will drop quickly as they start to burn fat. This can also happen at the end of a training session, so it is important to eat immediately after training (within ¾ hour). In this instance, sugar in the form of sweets, a drink etc is useful.
For important competitions requiring peak performance, swimmers should start loading with 'slow burn' carbohydrates 2 -3 days beforehand. Fat intake should be minimised on the last day.
As with any exercise, fluids need to be replaced when swimming to avoid dehydration. The warmth of swimming pools increases the swimmer's risk of dehydration. A 2% loss of body fluids causes a 20% drop in performance.
Swimmers need to drink during training sessions and between swims at competitions and should always bring a sports bottle of chilled water or diluted juice to poolside. The equivalent of at least half cup of fluid every 15-20 minutes is recommended.
The best drink is water. Sugary drinks should be avoided because sugar can inhibit the re-hydration process. Sugar based drinks such as fruit juices and squashes should be diluted with water by at least 5 parts to 1. Fizzy drinks such as cola and lemonade must also be avoided (the gas can also induce vomiting).
Some (expensive) 'Sports drinks' are available. If choosing these, only use the ISOTONIC ones. The HYPERTONIC or 'Energy' drinks are too high in sugar.
Some simple rules
• Eat a varied diet with lots of starchy carbohydrates and less fat.
• Swimmers should eat 1-2 hours before swimming. Food eaten prior to swimming should be predominately 'slow burn' carbohydrate, low in fat and low in sugar, e.g. Pasta with simple sauces (not cheese or meat), basic pizzas, bread, potatoes, rice, cereals.
• Get into the habit of drinking plenty of fluids, and bring plenty of low-sugar drinks to the pool.
• Snacks are needed during competitions, e.g. Bread rolls, bread sticks, pasta, cereal bars, biscuits, sweets.
• Eat something soon after swimming. This can be high in sugar.
If you need further help or suggestions, talk to your coach.