If you eat correctly, you can give yourself the energy to do a number of races in a Meet and you can even help yourself to go faster. This is no gimmick, but scientific fact. Lactic acid slows you down, but regular eating of plenty of fruit and vegetables can counteract Lactic Acid and result in its affecting you less.
Energy comes from carbohydrates. Swimmers should have a diet which is high in carbohydrates and as you get closer to competition you should eat more of them, and during competition you should eat little else.
Most importantly, you should not eat more protein and fat.
Carbohydrates include: cereal, bread, potatoes, pasta, pizza, rice, spaghetti, fruit - especially bananas - fruit juices, cake, ice-cream, yoghurt, bars and popcorn.
In the last 3-5 days before a Meet, you should concentrate on carbohydrates. For the few days involved less protein etc. won't matter but the energy from carbohydrates will. You should start weeks before - to get used to the diet.
If you increase carbohydrates and don't decrease fat intake then you will put on weight and swim slower.
So the rule is, eat a little and often. Avoid one or two meals a day. Eat before morning training, after morning training, at school break, at lunch time, after school, at tea time etc.
On the day of the Meet, take cereal, fruit juice, toast and milk. Avoid "Fast Food" outlets at breaks and concentrate on the carbohydrates listed above.
Never eat fries and greasy food. Never eat strange food. Keep it simple and eat often.
The other vitally important element in your diet is FLUID! Whether it is water, fruit juice, diluted squash or a sports drink doesn't matter. The point is to drink often. At least 1 litre of fluid for every hour that you train. During a Meet, you should have a bottle and sip from it regularly. If abroad or unsure, do not use tap water, and never use ice.
What you eat is your race/training fuel. Ensure it is 5 Star!
Try this link for info on kids' health