What should I eat in the days leading up to my half marathon?

Are you preparing for a half marathon? It's great that you are also thinking about preparing your nutrition plan! This can be an important link in completing this distance or improving your personal record. How much exactly should you eat prior to the race? And is it necessary to drink something along the way? In this blog you can read what you should eat and drink to make your half marathon a great success.

Storing carbohydrates

In terms of nutrition, the final preparation for your half marathon starts about 36 to 48 hours prior to the start. The day prior to the marathon should be all about storing carbohydrates (carbo-loading). This ensures that the glycogen stores in your muscles, which serve as a fuel tank for the necessary carbohydrates, are filled to the maximum. Exactly what and how much you should eat to load up on carbohydrates depends on your body weight, among other things.

The night before the marathon, you tick off the carbohydrate stacking. At that moment, you know that the fuel tank in your muscles is filled to capacity and that it will not be emptied again during the night before the start. This means that on the morning of the race, you only have to fill the (considerably smaller) glycogen supply in your liver. The body continuously draws energy from this fuel tank (among other things to provide the brain with fuel), which means that it is partially empty in the morning after waking up. For this reason it is advisable to eat a carbohydrate-rich breakfast (or lunch, if you are not getting an early start) to get the last of the fuel into the body's reserves.

The last 3 hours before the half marathon

Aim for an amount of +- 2-3 grams of carbohydrates per kilogram of body weight. For someone weighing 70kg, that amounts to +- 140 to 210 grams of carbohydrates. To ensure that all of this has been digested and absorbed before the start of your race, and to prevent stomach/intestinal problems, it is advisable to eat about three hours before the start. Also make sure that the meal is easily digestible, especially if you know that you have a sensitive stomach when running. Choose low-fibre products (such as white bread, cornflakes or rice pudding) and add liquid sugars (such as honey, jam and fruit juice). Avoid products that are high in fat and/or protein, such as eggs, (full-fat) dairy products, cheese and meats. Also remember to drink plenty of fluids. Aim for at least 500 ml of fluids, but above all check the colour of your urine. It should be relatively light in colour to be sure that your fluid balance is in order. See below for an example:

Runner of 70kg (goal = approx. 140-210 grams of carbohydrates)

 

After your breakfast, get plenty of rest to properly process and absorb all the nutrients. This is crucial to prevent gastrointestinal complaints during the marathon, and requires at least 2-3 hours, depending on the specific breakfast. If you want to eat something small in the run-up to the start, choose a light, carbohydrate-rich snack. This could be a ripe banana, but also an energy bar such as the Amacx Fast Bar or Energy Nougat. In the final hours before the start, don't forget to drink enough.

Basic principles for a successful half marathon

As soon as the starting gun has been fired, your competition nutrition plan comes into effect. The most important principles are:

1. First and foremost, make sure you have a competition nutrition plan. Eat and drink at the planned times, even if you feel even better than expected or if you are not hungry or thirsty. Try to stick to this plan, but don't forget to make small adjustments if necessary (for example, if it gets warmer than planned, or if you unexpectedly experience stomach or intestinal problems). Train this competition nutrition plan regularly to train your stomach and intestines to process these nutrients during exercise!

2. Carbohydrates and fluids are central to any competition nutrition plan. Make these two nutrients central to the competition nutrition plan and set clear and achievable hourly target intakes for both (see below).

3. Be well prepared and avoid surprises. So make sure you have the products you have trained with and that you know you tolerate well. Know where the organisation's supplies are and what is provided there. If you need other products or need products at other times, arrange this yourself.

Avoid exhaustion and keep your energy up

Although not eating or drinking during the half marathon is still quite common, it is certainly not recommended for strenuous exercise of 75 minutes or longer. Therefore, aim for a carbohydrate intake of at least 30 to 60 grams of carbohydrates per hour during the half marathon to ensure that the fuel tank in your muscles does not become depleted. As soon as these glycogen stores are empty, you will experience the well-known ‘hanger’. Therefore, try to take an Amacx product from the Energy Line regularly, once or twice an hour. The most obvious choice is to take an Amacx Drink Gel once every 30 to 60 minutes. These gels are very easy to digest, provide energy at lightning speed and can be consumed without additional water. However, if you prefer one of the bars from the Energy Line, or Energy Drink, then of course these can also provide the necessary fuel.

Make sure you drink enough

In addition to energy (carbohydrates), your body also needs sufficient fluids. When the temperature is relatively low and you do not sweat much, you may not need to drink at all or hardly at all during a half marathon. However, if it is very warm and/or you sweat a lot naturally, it is important to compensate for some of the sweat loss while running. By drinking enough, you can prevent a significant loss of performance in the final part of your marathon. The basic principle during the race should always be to lose a maximum of 2 to 3% of your body weight through sweating. A person weighing 70 kg can therefore lose a maximum of about 2.1 kg during their half marathon before a serious loss of performance occurs.

Therefore, try to measure your sweat loss in advance during more strenuous training sessions as follows:

1. Weigh yourself shortly before the start of the training session, without clothes and preferably after going to the toilet.

2. Do your training as usual. During the training, keep a record of exactly how much you eat and drink. Also record the temperature and humidity.

3. Immediately after the training, dry the sweat from your body, go to the toilet again and weigh yourself again.

Normally, you will lose weight during a strenuous workout. For example: an athlete weighs 70 kg prior to his training, he drinks nothing during the one-hour training and weighs 68.8 kg afterwards. His sweat loss under these circumstances is 1.2 litres per hour. If the expected finishing time of this runner is around 1.5 hours, he will lose a total of +- 1.8 litres of sweat (= 2.5% of his body weight). This would be sufficient not to drink during a half marathon, without compromising performance. However, if the expected finishing time is around 2 hours, the total sweat loss will be 2.4 litres (= 3.4% of body weight) and it is strongly recommended to drink at least 500ml during the half marathon.

Optimise your preparation and performance

Don't forget that a balanced diet, tailored to your training schedule, also offers great added value earlier in the preparation. This will allow you to make more progress from each training session and you will ultimately be in even better shape when you appear at the start of the race. Also, don't forget to train your race nutrition plan during a few longer/harder training sessions in the run-up to the half marathon. This is necessary to train your stomach and intestines to absorb and process the necessary nutrients during exercise, without resulting in stomach or intestinal complaints. Caffeine can also give an extra boost during the race. For example, you could choose Amacx Caffeine tablets.

In summary:

• Start carbo loading 24 to 36 hours prior to the half marathon. The basic principle is approximately 10 grams of carbohydrates per kilogram of body weight per day. This ensures maximum muscle glycogen stores.

• Eat a carbohydrate-rich and easily digestible breakfast about 2 to 3 hours before the start. The basic principle here is about 2 to 3 grams of carbohydrates per kilogram of body weight. This meal ensures maximum liver glycogen stores.

• If necessary, have a small carbohydrate-rich snack such as a ripe banana or an energy bar from the Amacx Energy Line one hour before the start.

• During the final hours leading up to the start, remember to drink enough. Check the colour of your urine: if it is light in colour, you know that your fluid balance is in order.

• During the marathon, aim for 1 to 2 products from the Amacx Energy Line per hour, to achieve an intake of 30 to 60 grams of carbohydrates per hour. Gels are the most obvious choice for this.

• Determine your individual sweat loss in the run-up to the marathon and adjust your fluid intake accordingly during the marathon. The basic principle here is to lose up to a maximum of 2 to 3% of your body weight during the race.