For many runners training for a half marathon is the moment the penny drops that nutrition isn’t just a case of ‘winging it’ and the realisation strikes that nutrition is actually pretty important when it comes to performance!
So Why is nutrition So important for A Half Marathon?
During exercise the body uses its fuel stores (a mixture of carbohydrate stores (or often referred to as glycogen stores) and fat for muscular contraction. Unfortunately, these stores become depleted quickly and without ‘topping up’ after approx. 60-90mins of prolonged exercise our fuel supply will run out. Depleted fuel stores can result in some unpleasant side effects – dizziness, fatigue, reduced performance, low blood sugars, disorientation to name but a few! The rate or speed at which you deplete your fuel stores is also dependant on the following factors: –
- The intensity at which you exercise – the faster you run for example the quicker you will deplete your stores as carbohydrate will be your primary fuel source.
- Your pre-training / Race nutrition – If you have eaten well before training or a race you will have fully prepped glycogen stores, if not your tank will already be running ‘on low’ this means your stores will be depleted sooner and you will need to fuel very quickly!
With this in mind there are two key messages for a Half Marathon
- Pre-Race Nutrition and hydration needs to be optimised
- Fuelling during Training and Racing is essential for performance.
Let’s look at each message in turn
- Pre-Race Nutrition and hydration
Prior to a Half Marathon Start topping up your glycogen stores in the 48hrs prior to the Race not just the 24hrs before! Snacks are an easy way to boost your carbohydrate intake, aim to have a snack mid-morning, mid-afternoon and at bedtime: Some suggestions could be: –
- A piece of Fruit and a cereal Bar
- 2 slices of Malt loaf or a toasted teacake
- Fruit smoothie
- Fruit and yoghurt
- Slice of Toast with honey /peanut butter
- Small bowl of cereal and milk
Don’t forget to hydrate as this helps you store the carbohydrate more effectively. Focus on quality of carbohydrate as well as quantity. The day before the race try not to have your evening meal too late so that you wake up feeling hungry on race day and choose carbohydrates that are easy for your body to digest e.g. Rice / cous cous / quinoa and couple with easily digested protein sources such as chicken turkey or fish.
Race Day Nutrition
On the morning of the race providing you have prepared well in the days beforehand your race day breakfast is just a top –up but aim to have a meal that you have tried and tested in training. Also make sure you are well hydrated! Some good example of a good pre-race breakfast:
Toasted Bagel with peanut Butter and Jam + Glass of Orange Juice (diluted)
Porridge (40-60g) with milk, honey and fruit + Orange juice (diluted)
Often the time between breakfast and the start of a half marathon can be several hours therefore make sure you have at least 30g of carbohydrate in the 30mins before the start of your race. Some examples of how to achieve this: –
- Informed Sport Isotonic sports Drink 500ml
- Energy Gel
- Energy Bar
- 6 Jelly babies
Fuelling Your Race
During your race After 60-90mins fuel stores will become depleted however this will depend on how fast you are running and how well you have fuelled in the days prior to and the morning before the race. To prevent running out of fuel it is important to start to re-fuel before your stores become depleted. Guidelines recommend at least 30g of carbohydrate per hour to fuel a race > 90mins in duration. The optimum timing for re-fuelling differs between athletes but most start fuelling after 30-40mins into the race.
Your choice of fuel will depend on your personal preference, what you can tolerate and what you have practised in training. If you are running over 90mins you also need to pay attention to your hydration, an ideal choice for fuel and fluid during a half marathon would be an isotonic sports drink containing 6-8 % Carbohydrate and electrolytes to help replace those lost in sweat during the race.
Other alternatives providing Approximately 30g Carbohydrate would be: –
- Energy Gel (1 – 1 1/2 depending on brand)
- Energy Bar
- X1 Banana
- 6 Jelly Babies
- 3-6 wine gums (depending on brand)
Top Tip 1. – Look at your Race day pack well in advance of your race or contact the race provider to ask what the course nutrition will be and at what stages along the course the feed and hydration stations will be. This will help you to plan your fuelling race day strategy and will also mean you can practice using the nutrition available on race day.
Top Tip 2:– An important tip when consuming energy gels is to make sure that you drink 150-200mls of water with each gel as otherwise they can upset your stomach. Avoid leaving it to race day to try new gels/ products to fuel with, the more your practice your race nutrition the better prepared you will be and the more ‘trained’ your digestive system will become if using sport specific nutrition products.
Recovery at the end!
Lastly recovery after a race is essential to re-hydrate, replenish glycogen stores and promote muscle recovery. Aim to recover with 1g/kg Carbohydrate and approximately 20-25g protein for optimum recovery. Then congratulate yourself for all your hard work and effort!
Enjoy your Race!
Victoria Prendiville BSc (Hons) Dietetics PG cert Sport and Exercise Performance Nutritionist.