ON YOUR MARKS, GET SET... EAT!
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The Montreal Marathon is just around the corner! Whether you're registering for the marathon, the half, the 10K or even the 5K, your diet can have a huge impact on your performance.
What you choose to eat before, during and after the race can make a difference on your time, but also on the level of difficulty during the race (pleasant or painful experience) as well as on the intensity of the aches and pains afterwards.
Before, we stock up!
The human body, comparable to a machine, needs fuel to function and carbohydrates are the main source of energy for the body during exercise.
If you want to avoid "hitting the wall" during the race, i.e. being unable to continue due to sudden and intense fatigue, you need to make sure that your glycogen reserves, i.e. the carbohydrates stored in the liver and muscles, are full.
To do this, the meal eaten 3-4 hours before the race, breakfast in the case of the Montreal Marathon, must be sufficiently rich in carbohydrates, with low-fat proteins so that digestion remains comfortable during the race.
Examples of pre-race meals:
Oatmeal cooked with soy milk and a banana
Toast with cottage cheese and melon
Smoothie with banana, orange juice, yogurt and wheat germ
The quantities to be consumed will vary according to the weight of the runner and the intensity of the race.
For an event lasting more than 90 minutes, such as a half marathon or marathon, a glycogen overload is the best way to ensure that your reserves are full.
Glycogen overloading, also called carb loading, is a common practice in endurance sports. It is a short feeding protocol prior to the event in order to optimize glycogen reserves.
There are several variations of the protocol. It is possible to start with a glycogen depletion phase through intense exercise and/or a low carbohydrate diet a few days before the race. This phase would possibly increase glycogen storage capacity, but it has several disadvantages: difficult to perform, fatigue, weakness, irritability, dizziness, etc. Several studies show that this phase is not necessary to maximize glycogen stores. The overload phase can start 1 to 3 days before the race: we go from a normal diet to a diet rich in carbohydrates.
However, this is not a magic formula that works for everyone, some people may even feel weighed down. It is therefore essential to try the overload at least once before the big day.
The nutritionist will be able to determine the right amount of carbohydrates and make an overload plan tailored to your needs.
And we drink water!
Adequate hydration is essential for athletic performance. To avoid arriving dehydrated at the starting line, it is recommended to drink 500 to 600 mL of liquid, ideally water, 2 to 3 hours before the event and again 200 to 300 mL 10 to 20 minutes before the start.
During, we provide the fuel!
For a race of less than an hour, water is sufficient. However, regardless of the level of the race, maintaining an optimal state of hydration is essential.
Body water plays a very important role in the thermoregulation of the body. Even mild dehydration (i.e., a water loss of about 1% of body weight) can negatively affect the body's ability to cope with physical exertion, especially in hot weather.
Therefore, one seeks to drink to replace losses through the skin, sweating and breathing during the run. To avoid being slowed down by a stomach full of water, it is best to take small sips of water regularly. It is recommended to drink according to thirst, but to know your fluid needs (for example, a fluid intake of about 200 to 300 mL every 10 to 20 minutes).
Be careful, drinking too much water could be counterproductive, even dangerous if there is an electrolyte imbalance.
Moreover, for a prolonged effort, you want to avoid not only dehydration, but also hypoglycemia and electrolyte loss.
It is obviously more difficult to eat during the race because the body is in motion and the digestive system is also in motion, which does not allow the ingestion of large quantities. Instead, we opt for efficiency: Sports drinks (commercial or homemade), sports gels or jujubes, dried fruits, energy balls, banana bars, etc. We want foods that are easy to ingest (liquid or requiring little chewing) and rich in carbohydrates and electrolytes (sodium, potassium, magnesium) and low in fat and protein.
The choice of food obviously depends on food preferences and digestive capacities, but especially on the carbohydrate intake. For a race lasting 1 to 2.5 hours, runners should consume 30 to 60 g of carbohydrates per hour and for a race lasting more than 2.5 hours, 80 to 90 g of carbohydrates per hour.
Afterwards, we recover!
Once the race is over, you're not done eating!
The objectives are to replenish your glycogen reserves, to repair the muscular micro-tears produced during the effort, to recover the electrolytes lost through perspiration and to rehydrate.
The snack or meal taken within half an hour of the event should contain 5 to 20 grams of protein and 15 to 60 grams of carbohydrates. The amount depends on the intensity of the event: the need will obviously be higher for a marathon than a 5km.
Moreover, for prolonged efforts, carbohydrate intake will be higher to replenish glycogen reserves. The runner will need 1 to 1.2 g of carbohydrates per kilogram of body weight every hour for the first 4 hours after the event. So for a 60 kg person, 60 to 72 g of carbohydrates per hour.
To replace electrolytes, we will look for foods rich in potassium, magnesium and particularly sodium which will stimulate thirst and push us to rehydrate.
Of course, we must drink a lot of water to compensate for the losses, until the color of the urine is clear again.
Example of snacks to eat after the event:
Chocolate milk or soy beverage
Fruit and dairy smoothie
Example of a meal to eat after the event:
Egg and cheese sandwich
Pasta with tomato sauce
For optimal food preparation for this event, do not hesitate to consult a nutritionist!
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Anahite Afshar, Nutritionist-Dietitian
Rosenbloom, Chrisitine A; Coleman, Ellen J (2012). Sports Nutrition: A Practice Manual for Professionals 5 th Edition. United States of America: Academy of Nutrition and Dietetics, 499p.