INTRODUCTION

Radical changes in diet are not good, so you should adapt to your new habits little by little.
Guidelines to follow to improve personal habits:

• Reduce protein intake (meats and fish) to a maximum of three days per week.
• Consume fewer frozen foods and ready-made meals.
• Reduce fried foods as much as possible and avoid highly processed sweets.
• Increase the intake of rice, pasta, vegetables and greens, fruits, legumes, nuts and seeds (it’s best to buy them with shell).
• It would also be important to take in the morning a daily teaspoon of honey (better if authentic) and another of extra virgin olive oil.

Following these simple guidelines, the blood will thicken less (as fewer residues will circulate through it), the liver will work less (so side stitches will disappear) and the number of red blood cells will increase, among many other advantages.
In the medium term you will feel much better and for the same effort your performance will be much greater.

To reach the marathon in good shape it is key and essential to always maintain good ferritin levels. If it drops to minimum levels everything else will be useless.

Foods rich in iron

Below I list foods rich in iron in order from highest to lowest proportion per serving (This is not equivalent in grams; some servings are 75 grams and others 250 grams).
Those with the most “Fe” per serving are around 22 mg (per serving), and in the list the one with the least has 4 mg (per serving).

Foods rich in Fe:
Anchovies, Fresh Bonito, Pork Liver, Brewer’s Yeast, Cocoa Powder, Dry Soy, Lentils, Saffron Milk Caps, Blood Sausages, Clams or Oysters, White Beans, Squid, Mussels, Dried Apricots, Brains, Veal Liver, Almonds, Hazelnuts, Cannelloni and Dried Figs.

You can also take every morning, before breakfast, some iron complex with a natural orange juice or a vitamin C tablet.

Some advice on nutrition and ergogenic aids (Extracted from an article I published in Runner's World magazine)

On days of hard training sessions or long progressive runs, when running between 70% and 85% of VO2Max, it is very important to eat foods rich in carbohydrates. High glycemic index carbohydrates (or fast-absorbing) should be consumed right after training or racing — such as honey, molasses, or glucose. Medium glycemic index carbs should be taken three hours before or three hours after training — such as pasta, rice, bread, or pizza. It is recommended to consume between 150 and 300 grams. And low glycemic index carbs should be eaten in meals furthest from training.

In the marathon you should not take gels with fast-absorbing carbohydrates as they may produce the opposite effect to the desired one. I have heard of a new slow-absorbing one ideal for marathons, the Energy Boost Gel (from the Victory Endurance line, by Weider). Caffeine increases fat oxidation in the first minutes, but does not affect the rate of glycogen use. It does improve sports performance somewhat, and above all affects the nervous system. It is advisable to drink a single espresso coffee less than an hour before racing.

The maximum daily intake of protein must depend on the effort performed. This range varies between 1 and 1.6 grams per kilo of body weight. A 70 kg runner would need to consume between 90 and 120 grams daily, and can obtain it from a normal diet without supplements. The best proteins are egg white and whey.

HYDRATION

Long-distance and long-duration training sessions require us to ensure a sufficient supply of water to our body. The opposite would be harmful.

Function of water in the body

Water, besides refreshing and relieving, fulfills two important functions:
1st. The one related to heat loss processes, or thermoregulation.
2nd. The one related to the transport of oxygen through the blood and nutrients to the muscles, or cardiovascular.
Sweating, through whose evaporation we cool the body, is essential so that the body does not overheat. In hot weather it is ideal to train with little, very breathable clothing, such as cotton or Coolmax. The amount of sweat produced depends on the person; generally those who are less trained sweat more, as they run less efficiently, use a greater amount of carbohydrates for muscle work and take longer to recover.

Some runners can lose 2 to 3 liters of sweat in a long-distance training session done in the heat, as may be your case. Losing so much water through sweating, if not properly replenished, produces a decrease in blood flow. Hence the importance of hydrating a lot and well in summer, and drinking every five kms during long-distance races; the intake of fluids during them helps to replenish losses, protecting from the harmful effects of dehydration on muscle strength, endurance and coordination. In fact, if rehydration were left entirely to thirst, the runner could take several days to restore fluid balance after severe dehydration.

In summer you must not wait for the sensation of thirst to drink, as this would indicate a certain degree of dehydration. An effective practice is to drink two glasses of water with mineral salts before heading out to run, and twice that amount when finishing. If you are curious to know how much water you lose in a training session, the best way is to weigh yourself before leaving and upon returning. In general, when the loss is 1/2 kg, the amount of water to replace is approximately 1.5 liters, always to be taken in small sips.

Sports or isotonic drinks

These are aqueous solutions that contain minerals, soluble carbohydrates and vitamins. The mineral salts we ingest with food are found in body fluids as electrically charged particles, hence they are also called "electrolytes". Ingesting isotonic drinks, especially in hot weather, allows for faster and better recovery after big efforts, minimizes the risk of muscle cramps and rehydrates more quickly. In the case of taking them in races, caution is required, as if you are not used to them they may cause diarrhea or stomach pain.

Good drinks of this type are those you can make yourself at home. They are made by mixing mineral water (rich in sodium, magnesium and chlorides) with the juice of one lemon, a tablespoon of sugar (preferably cane sugar) and a pinch of baking soda; in an approximate ratio of 1 liter of water per lemon. It is advisable to drink it between 7 and 13 degrees, that is, chilled.
Cold liquids leave the stomach faster and thus avoid the sensation of bloating. On the market there are drinks of this type and powdered mixes to blend with water such as Iso Energy, Flectomín or Isostar. The first is quite better. In these cases they should be mixed in a very diluted proportion. If taken in cold or mild weather, one coffee spoon per half liter of water should be used, in hot weather the dose is doubled, that is two teaspoons per half liter. Less efficient are Aquarius, Powerade, Gatorade and similar ones.

Never experiment with these drinks during a race; try them first in training.

In Summary

• Fluid must be taken before, during and after any race.
• Drink two glasses of water before going out to train and twice as much afterwards.
• You must not wait until you are thirsty to drink, as exercise delays the appearance of this sensation.
• When you feel thirsty you have already lost an excess of water and electrolytes, and fatigue has appeared.
• Sweating creates a relative state of dehydration; if it is excessive and the fluids lost are not replenished immediately, blood volume decreases and core temperature can rise to dangerous levels.
• Master runners are more vulnerable to the effects of heat.
• A 4% loss of body weight during the race significantly hinders heat dissipation and compromises cardiovascular function, and therefore the chances of performing well.
• The main goal of fluid replacement is to maintain plasma volume so that blood flow and sweating remain adequate. Cold fluids are absorbed more quickly.
• The loss of electrolytes through sweating is easily replenished by adding a small amount of sea salt to food.
• Training clothing should be light and loose to aid sweat evaporation. Preferably in light colors (they reflect the sun’s rays), as opposed to dark colors that absorb light and increase body temperature by radiation.
• The best times to train on hot days are early in the morning and late in the day, and if possible in shaded areas.