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Following on from the previous article “The Nutrition Pyramid” sports dietician Alexandra Cook will discuss the important issue of race day nutrition and how vital it is to help you perform at your best. She will point out specifically what will be available at the South Downs 100K aid stations, and what the best options are to keep you going strong through an ultramarathon.

Fuelling your A game

To become an ultra runner is to overcome suffering. Accept that, and there will never be a finish line you can’t cross. During an ultra marathon, you’ll have to ensure physical pain, there is no way around it!”......

For many of you that have run ultras, you can probably identify with the above quote. Although suffering at some point in an ultra marathon is to be expected, there are strategies we can put in place to minimise or control them when / if they arise. An ultra is not just about running , it’s about strategy. Strategy on how you are going to mentally and physically tackle the distance but also on how you are going fuel it.

The main aim as an ultra runner is to maintain a high energy output over a long time. During the race, energy expenditure is huge, so you must pay close attention to a nutrition and hydration plan, as failure to do so can ruin your chance of success. However, my time as a sports dietitian and ultra runner has shown me that over these long distances sometimes the science does not always hold true to the reality of what a runner can manage....So what really works? The main cause of fatigue during a run longer than 60 minutes is depletion of energy stores. Energy comes in the form of calories from carbohydrate, fat and protein. Out of the three, carbohydrate is more readily converted into energy and hence the body’s preferred energy source. But here lies the problem; we only have enough stored carbohydrate to last 90 minutes of exercise, compared to fat, where stores are thought to be able to fuel a runner for at least 1300kms! Therefore to combat this problem and prolong exercise time to exhaustion, the runner must be able to take on carbohydrate during their run, keeping blood glucose levels up and preserving the stored glycogen for as long as possible.

The Science

So let’s have a look at just how much carbohydrate you need to ensure you reach that finish line. The “Gold Standard” for carbohydrate consumption during exercise is approximately 60g per hour (based on the ability of 1g/min carb absorption) with a maximum possible absorption of 90g/hour if taken in a 2:1 blend of glucose:fructose (known as dual carbs ). This combination increases absorption rate over time, resulting in very high oxidation rates.

There has even been a suggestion of higher amounts being tolerated when a study back in 2020 (1) published findings on a small co-hort of elite mountain marathon runners looking at the effects of 120g/h of carbohydrate during a mountain marathon . It showed that some (but not all) of the subjects could tolerate this massive amount of carbohydrate (equivalent of 5 1/2 gels) and showed less muscle damage 24 hours post race compared to the group taking lower amounts of carbohydrate. Although quite an exciting finding in the world of sports nutrition, more studies need to be done.

Next up is protein. Many ultra runners like to take protein alongside carbohydrate during races but does it improve performance? A review in the Journal of Sports Medicine (2014) concluded that although protein ingestion during prolonged exercise may inhibit muscle protein breakdown, it does not further enhance performance capacity when compared to the ingestion of ample amounts of carbohydrate alone.

The Reality

So we are clear on the science that it is possible to absorb between 60-90g carbohydrate (and possibly 120g) over the hour and protein ingestion alongside carbohydrate won’t necessarily improve our race performance but how does this translate into reality?

Tolerating 120g of carbohydrate per hour for the length of an ultra for most runners is unlikely. 90g of carbohydrate per hour is possible but not for the weak stomached, especially over races lasting longer than 3 hours! Not many of us can tolerate 4 gels, or 2 energy bars every hour for 12 hours. Not only is it tough on the stomach but also taste fatigue will set in pretty early and the logistics of carrying 24 energy bars in our back-pack over 100 kms would be a challenge in itself. The reality of it is, during ultras we need to survive and to survive we need to be flexible. If you aim to consume 30-60g of carbohydrate an hour, you will find yourself in a strong position. Unless you are among the elite few, speed is not of the essence but keeping one foot in front of the other is the aim of the game. If you go slowly enough, for long enough, its gets to the point where you can use anything for fuel, just so long you take in the calories and your stomach can tolerate it. Early on in the race you can survive on gels and other carbs but after 4 hours taste fatigue can set in and your body starts craving more. Although, unlikely to improve performance, adding one part protein to four part carbs may keep hunger at bay (protein takes longer to digest) and may provide some “comfort” six hours into a long race.

During the South Downs 100K, there are going to be 7 very well stocked aid stations that will have a large variety of food and drinks to hopefully appeal to any cravings or fuelling needs. For example, a variety of sweet and savoury sandwiches (vegan, gluten free options) sweets, sausage rolls, bananas and watermelon, homemade vegan/gluten free biscuits and cakes, coke, Redbull, chocolate and also High Five gels, bars and energy drink (the main nutrition sponsor).

When to fuel

The longer we can preserve our stored carbohydrate, the better we will be fuelling when we run. If we can keep our blood sugar levels topped up, we can keep saving our stored carbohydrate for later. With this in mind, it is important to maintain your energy levels as early as possible. If you are waiting to take your first gel or drink until an hour into your run, your glycogen stores will already be getting low. The key is to start early at about 20 - 30 minutes in. Although you won’t necessarily be feeling low on energy, topping up the tank from the word go will only benefit you later in the race where fuelling may become harder due to fatigue and potential stomach problems.

Secondly, take note of how many aid stations there are. You have 7 aid stations in the race, most are approximately 10km apart, except for a stage in the middle where there is 17km between checkpoints 3 & 4. You need to ensure you have enough drink / gels / food to get you between check points where you can restock. Alternatively you may prefer to be totally self sufficient and have a drop bag at the half way checkpoint, with your own personal nutrition options, to replenish your stock. Estimate how long you think it will take you between each checkpoint. You may find you do not need to stop at everyone and re stocking every other check point will be enough.

Practical Top tips for your plan

  1. The science provides the guidelines but be flexible, as no matter what the science says, you are more constrained on the day by what your stomach dictates.
  2. To start, trial 20-30g carbohydrate per hour, little and often and aim to work up to 50- 60g/hr....remember your gut is trainable.
  3. Use your long training runs to conduct experiments of how much and what type of fuel you can tolerate.
  4. You will find High five products throughout the course of the South Downs 100K. If you train with them now, you will can rely more on check point nutrition and not have to carry so much with you in your hydration vest.
  5. Set your watch time to bleep every 20-30 mins to remind you to fuel.
  6. Start fuelling early whilst the gut is fresh and absorbs carbs easily, things might not be so easy a few hours into the race!
  7. The Golden Rule - don’t follow what others do. Remember we are all individual and what works for you won’t work for someone else.

    For your individualised fuelling strategy please get in contact and I will give anyone racing 15% of their consultation.

    Luc JC Van Loon, Is there a need for protein during exercise, Sports Medicine 2014 , 44 (suppl 1): 105 - 111

    Viribay A, Arribalzaga S, Mielgo-Ayuso J, Castañeda-Babarro, Seco-Calvo J, Urdampilleta A. Effects of 120 g/h of Carbohydrates Intake during a Mountain Marathon on Exercise- Induced Muscle Damage in Elite Runners. Nutrients 12(5), 1367, 2020. doi: 10.3390/ nu12051367.

To find out more about Alexandra visit www.thesportsdietitian.co.uk or follow her on Instagram thesportsdietitian.

Previous Blog Posts:
The Nutrition Pyramid (Part 2)
The Nutrition Pyramid (Part 1)
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