Regardless of your fitness and training miles clocked up, getting your hydration and nutrition right on race day is going to maximise both your performance, and enjoyment of the event. To help you get it right on your marathon day, we’re taking an in depth look at race day nutrition for marathon running.
We cover what to eat in the hours and days before a marathon, when to take on energy during the event, how much fuel is required for a marathon and we also look at some of the best carbohydrate sources for during running. We finish with 5 takeaway tips on marathon fueling, and an example nutrition plan for a 4 hour marathon.
At A Glance... 5 Quick Fire Marathon Fueling Tips
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Carb Load - Increase your carb intake in the 2 or 3 days prior to the event, ideally without increasing overall daily calories. Achieve this by minimising high fat and fiber foods. Top up energy stores with a high carb, low fat breakfast 3-4 hours before you start.
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Start hydrated - Hydration starts in the days before the event and remains important throughout the event. Consume water with electrolytes to avoid diluting the body’s natural balance. Top Tip - Have a bottle of electrolyte drink to hand on race morning, e.g. while travelling to the event.
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Fuel On The Go - Carbohydrates are the easiest energy source to consume, digest and use whilst running. Research suggests 60-90g of carbs per hour during prolonged endurance events, so VOOM Pocket Rockets or Fusion Fuel are convenient and stomach friendly ways to achieve this.
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Hydrate during - Good hydration aids performance and allows the body to more easily absorb the energy you’re feeding it during the event. A full spectrum electrolyte drink, such as VOOM Hydrate, replaces the salts you’re sweating out, aids fluid uptake and keeps you moving along the course!
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Practise the plan - Training the body, and in particular the gut, is a real thing to prepare yourself to more efficiently and more comfortably absorb higher carbohydrate intakes whilst running. Whatever strategy you plan to use on race day, we recommend practising it during your longer training runs.
What to Eat in The Days Before a Marathon
Carbo loading is a popular phrase amongst runners and endurance athletes, but what is carbohydrate loading and how can you use carb loading to boost performance?
Carb loading is a strategy used by many athletes to maximize the storage of glycogen in muscles and the liver, which can improve endurance performance. The increased glycogen stores can help delay fatigue during prolonged exertion by maintaining energy supply to the muscles.
To effectively load carbs, the increased carb intake should be paired with a reduction in exercise, also known as a taper. It's crucial to taper exercise duration and intensity during this period to allow the muscles to store more glycogen. About 3 - 4 days before the event, athletes should aim to consume 7-10 grams of carbohydrate per kilogram of body weight per day, focusing on high-carb foods like pasta, rice, bread, and fruits. Too much fiber can also cause irritation of the stomach and digestive system during an event, so often white carbs can be better than the whole grain equivalents you may usually enjoy.
Carb loading isn’t necessarily about increasing the total calories per day, but more a case of manipulating the balance of macronutrients, so avoiding too much fat or protein at this time helps with the carb load. One mistake many runners make is to simply eat more and use ‘carb loading’ as an excuse to indulge, so aim to get 70 or even 80% of your daily calories from carbohydrate.
Avoid excessive fats and proteins, as they don't contribute to glycogen stores. Loading should be done within the 3-4 days prior to the event for optimal results, allowing glycogen stores to peak without feeling overly full or sluggish. It's also important to stay well-hydrated during this time. In some circumstances an electrolyte drink can help achieve adequate hydration, such as VOOM Hydrate Smart which hydrates up to 40% more quickly than water alone. The electrolytes both aid water absorption into the body, as well as help maintain important functions in the muscles and nervous system.
What to Eat Before A Marathon (3 Hours to Go)?
The American College of Sports Medicine recommends 1 - 4g of carbohydrate per kg of body mass 1 to 4 hours before prolonged endurance exercise. Taking the example of a 70kg runner this would be 70 to 280g of carbohydrate in this period. 70g of carbs may be achieved with a bowl of porridge and a banana or handful of dried fruit. A VOOM Powr Beetroot Endurance bar can be another good snack to boost carbs offering 28g of carbs per bar with the added benefit of dietary nitrates to boost blood flow.
On the higher end of the scale, 280g of carbohydrates will take a little longer to digest and absorb into the body so, if you’re aiming for this level, eating around 4 hours before the event may be needed. As an easy, convenient way to boost carbohydrates you can supplement using a carb drink such as VOOM Fusion Fuel which offers easily absorbable carbs, as well as electrolytes to support hydration.
A ‘last minute’ top up of carbs helps ensure you start the event feeling your best, and this can be a time to use some caffeine too. We recommend eating 1-2 pieces of a VOOM Beta Blast Pocket Rocket, 15-30 minutes before the start. This will elevate blood glucose, reduce lactic acid build up with 2g beta alanine per bar, as well as give you a mental and physical boost and delay fatigue, thanks to 100 mg of caffeine per bar. The Caffeine Kick also works well here with 175m caffeine per bar, but without the beta alanine. If you prefer not to use caffeine then 1-2 pieces of Electro Energy will also support blood glucose levels.
During the 3 or 4 hours preceding the event it is easy to let hydration slip your mind, for example when driving to the event or registering. Make sure you have a bottle to hand, ideally with electrolytes in. We recommend sipping on 500-750ml of VOOM Hydrate Smart in the 3 hours before your marathon, possibly more if its particularly hot, or you know you’re a heavy sweater.
Why Should I Fuel During A Marathon
When the duration of exercise exceeds around 90 minutes, most people significantly deplete their glycogen stores which then require intra-exercise refuelling to maintain performance. This means taking on energy during your training or event to avoid ‘bonking’ or ‘hitting the wall’. Runners and endurance athletes should consume carbohydrates as the most readily usable energy source for the human body. Research repeatedly shows performance improvements when carbs are consumed during endurance exercise, and you’ll feel a whole lot better!
Whilst running the muscles are using lots of glucose and require an increased blood supply, meaning some other areas of the body, such as the digestive system, may receive a slightly reduced supply. For this reason simple carbohydrates are the preferred intra-workout energy source as they can be quickly and easily absorbed into the body. This is where some runners use energy gels, and others, who want twice the energy, reach for their Pocket Rocket!
How much do I need to eat during a marathon?
How much carbohydrate to take on board during an endurance event, such as a marathon, is influenced by two key factors: the duration and intensity of exercise. As the duration of exercise increases, so too does the energy requirement. On this basis, during a marathon the energy needed can vary significantly between an elite runner at just outside 2 hours, a club runner aiming to break 3 hours or a casual runner who may be on course for 5 hours or more.
Secondly, the higher the intensity you’re working at, the greater the carbohydrate intake required per hour. Considering the average heart rate during a marathon can vary between 65 and 90% of maximum heart rate, we again see that no one size fits all when it comes to carbohydrate intake. An elite runner who is exceptionally well trained may be capable of maintaining a heart rate of close to 90% of their maximum heart rate, whilst a recreational runner or someone just enjoying the day, rather than chasing a time, may be working at a much ‘easier’ intensity of only 65% of their respective maximum heart rate.
As a result of these factors, the most reliable way to consider carbohydrate intake for marathon running is by looking at grams of carbs per hour. Research recommends consuming 60-90g of carbohydrates per hour during moderate to high intensity exercise lasting upwards of 2.5 hours. The higher your relative intensity, the higher the hourly intake you’re likely to need. When taking on more than 60g of carbohydrate per hour the body will require a mix of multiple transportable carbohydrate sources - more on that later.
If you’ve not previously consumed much during your runs you may want to start with a lower carb intake of say 40-50g of carbohydrates per hour. The Pocket Rocket fits perfectly here, delivering 45g of carbs in four easy bites. We recommend one piece every 15 minutes to maintain a steady energy supply, without stressing the GI system.
What type of carbohydrates are best for a marathon?
Simple carbs are best during a marathon, also called sugars, because they can be more quickly absorbed into the body. At carb intakes much in excess of 60g per hour, a combination of both glucose and fructose is required, because glucose absorption is thought to be limited to a maximum hourly rate of around 60g. Fructose, which is absorbed via a different pathway, can account for additional carb intake above 60g, with research suggesting the highest possible rates of carbohydrate oxidation can be achieved with a ratio of 1: 0.8 of glucose to fructose.
As an example 90g of carbohydrate could be achieved by consuming 50g of glucose and 40g of fructose. Pocket Rockets contain a natural balance of glucose and fructose, and Fusion Fuel is scientifically formulated to that exact optimal 1 : 0.8 ratio, allowing the fastest possible energy absorption.
What should I eat during a marathon?
While it’s great to calculate these figures for carbohydrate intake, what do you actually need to eat to get those carbs? Easily digestible, fast-acting carbohydrates are best for during exercise, which is why there are a range of sports nutrition products which can support carb intake during your marathon.
Popular carb sources during running are jelly babies, bananas or energy gels, but we prefer the VOOM Pocket Rocket, which packs twice the energy of a gel. The Rocket offers a tasty, convenient and super-fast acting energy source to maintain your energy levels, without risking stomach upset. 1 cube every 15 minutes delivers 45g carbs per hour, or 1 piece every 10 minutes delivers approximately 66g per hour. Gradually delivering the energy throughout each hour aids stomach comfort whilst avoiding any ‘sugar crash’.
In the early and mid stages of a race we recommend using the Electro Energy which delivers 120mg of electrolytes per bar, in addition to fast-acting energy. In the latter stages the Caffeine Kick continues to deliver energy with the addition of 175 mg of caffeine per bar to reduce fatigue and give a mental and physical boost. As the bars easily break into four pieces it is convenient to pace your energy intake, whatever your chosen rate, and the caffeine gives you a real kick to finish strong!
For even more nuanced energy dosing, another option to consider can be using carb drinks instead of, or in combination with, energy bars or gels…
Carb Drinks vs Gels or Energy Bars for Running
Instead of energy chews, gels or bars some people prefer carb drinks, sometimes called energy drinks, to be able to consume energy in a liquid form. If you’re able to carry your own drinks, or are lucky enough to have supporters willing to pass you drinks, then this can be a great option, covering your hydration as well as your energy intake.
VOOM Fusion Fuel is a unique tri-carb energy drink packing an industry leading 90g of carbohydrates per serving. The unique blend allows faster absorption from the stomach and small intestine, giving you more energy, more quickly, whilst maintaining stomach comfort. In this way a 500ml bottle can deliver you 90g of glucose and fructose as well electrolytes to aid hydration, b-vitamins and amino acids to reduce fatigue.
For example those working at a high intensity may wish to aim for 90g of carbs per hour, so would just need to take on 500ml of Fusion Fuel each hour to be fully fueled and hydrated. Alternatively, if you wanted to aim for 60g of carbs per hour you could spread that drink over 90 minutes, and perhaps take a little bit of water from aid stations along the route.
Training the gut
There has long been advice on testing things before race day, whether its some new kit or your nutrition strategy. Now there is a growing scientific research base to suggest the gut can actually be trained to more efficiently absorb carbohydrates during exercise.
We would always recommend practising your fuel and hydration strategy during your longer training runs, and if you’re aiming to increase your hourly carb intake, do this gradually over a few runs. For example if you currently take on 45g of carbs per hour (2 gels), maybe try taking on 55g of carbs per hour (5 pieces of Pocket Rocket, one every 12 mins) in your next couple of long runs. Once comfortable with this perhaps try 65g per hour (1.5 Pocket Rockets, one piece every 10 mins), and so on.
What Should I Drink In A Marathon and How Much?
Hydration is as important, if not more so, than taking on carbs, and dehydration directly reduces performance, and makes it more difficult for the body to absorb energy from the stomach and intestine. As a general guide, 400 - 600ml of fluid per hour will be a helpful target for most runners to aim for during a marathon. This may be high in particularly warm conditions, and many runners may need to consider electrolytes too.
Water is a crucial, but so too are electrolytes within the body; sweating, which you're likely to be doing, depletes the body's electrolyte levels which are important for maintaining hydration levels in the body and muscle contractions. An electrolyte drink will not only replenish the electrolytes but also speed up the absorption of water into the body, meaning the fluids you drink will hydrate you more quickly.
If you aren't getting electrolytes from any other sources, we recommend taking on board one serving of VOOM Hydrate Smart every 60-90 minutes during a marathon. This can be carried with you, or sachets can easily be mixed with water on the aid stations.
Example Nutrition Plan for 4 hr marathon
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3 Days before : Increase carbohydrate intake, avoid high fat and high fibre foods.
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3 hours before : High carb, low fat meal, aiming for 1-4g of carbs per kg body weight, again avoiding high fiber.
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20 minutes before : 2 pieces Beta Blast (22g carbs, 1g beta alanine, 100mg caffeine)
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Hourly from Hour 1 to Hour 3 : 1 piece of Electro Energy every 10 to 15 mins (45 - 66g carbs per hour). In addition aim for 400 - 600ml fluid per hour.
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4th Hour - 1 piece Caffeine Kick every 15 minutes (45g carbs and 175 mg caffeine per hour). Plus 400 - 600ml fluid.
Best VOOM Products for Marathon Running
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Hydrate Smart - Learn More
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Beetroot Powr Bar - Learn More
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Beta Blast - Learn More
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Electro Energy - Learn More
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Caffeine Kick - Learn More
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Fusion Fuel - Learn More
Try the products mentioned in this article with free postage, plus a free resistance band in our VOOM Marathon Training Taster Pack. Simply enter the code ‘marathon’ at checkout.
