A swimmer needs to be lean to reduce burden on his arms and legs. Endurance is again an important factor while swimming.
Looking at both requirements, the best diet which can be prescribed for a swimmer would be the one which is rich in "easy to digest carbohydrates". The only diet which qualifies on this regard is a fresh fruit diet.
For one, its is the best food for human beings. The fact that humans are frugivorous is evident from three factors
1. We love animals, we don't look at them as prey. Its just that our habits have been spoiled through years of misuse. Would you look at a cow, lamb or chicken and want to rip it apart and eat it?
2. We have hands to pluck fruits. If you notice, only fruit eating animals have hands for examples monkeys, gorillas and chimps.
3. We don't have claws the way carnivores have
4. Our stomach cannot digest the cellulose present in grains the way birds and other grain eating animal do
5. We cannot digest green vegetables with the same efficiency as cows or other herbivorous animals. Most vegetables are rich in starch which mostly goes undigested.
Fruits provide you with all the essential minerals and vitamins in the required quantity no more no less. Protein requirement in human body is minimal mostly because 70% of it is recycled for reuse. The protein content present in fruits is less as required by the human body.
Three things
1. When you cook food vitamins and minerals become devalued and lost
2. Cooking food causes organic minerals to get converted to inorganic forms. This is harmful for the body.
3. The use of salts, condiments and other herbs stimulates the nerves and leaves you enervated and lacking in vitality.
4. Table salt is pathogenic and is a poison for any living organism. Athletes should be extra careful with their salt intake.
5. There is a tendency to overeat cooked food because of a taste perversion.
Eating cooked food leaves you tired, sluggish and over weight. There is a lot of energy expended in the digestion of cooked food.
The body takes a few minutes to digest fruits while it takes 3-12 hours to digest cooked food depending on the combination and type of food you have eaten.
Glucose is the fuel for human body. A lack of glucose results in lack of energy. Glucose is obtained from carbohydrates and nothing else. Fruits are rich in carbohydrates called monosaccharides, the only sugars that can be absorbed and utilized by the body.
Rice, refined sugar, wheat, starchy vegetables contain polysaccharides which takes more time to digest and assimilate. At times it is left undigested.
The best source of glucose for the body comes from a diet of fruits.