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February 20, 2023

Fuel Your Marathon Performance by Coach Rosie

Written by Rosie Edwards
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The early mornings, long workouts and countless miles are the engines that drive an athlete from the start to the finish line, but how do you fuel for the big day?

My name is Rosie Edwards. I am a professional marathoner from Great Britain and running coach. rosie

Recently, I had a fascinating conversation with a professional cycling coach. I was wanted to learn about the elite cycling world and their training. He emphasized that attention to recovery was paramount compared to the training itself.

I intuitively knew that nutrition and hydration are vital for not only competition, but for recovery into the next training session. Training at its simplest is stress, response, and adaptation. Appropriate hydration and nutrition (ie. Fueling) is paramount for the optimal response = improved fitness.

Glycogen (our body’s form of carbohydrate) is the main energy for our working muscles while it also assists in fat metabolism. In addition, glucose is the primary fuel for the brain. If the body is glycogen depleted then this can lead to physical (decreased force production, increased soreness, increased muscle weakness) and cognitive impairment.

Picture the last 10 km of a marathon when it is “go” time. If your cognitive function is impaired and your glycogen stores are depleted, responding to your competition's moves and staying engaged will certainly become a challenge.

How does fueling look for me?

Before the race and within training:

I aim for 7-10 g of carbohydrate/kg/day when in peak training. I lean towards low glycemic index or GI (slow release) carbohydrates including whole grains, fruits, vegetables, sweet potatoes, and lots of oats. Low GI is my preferred choice for preparation to avoid spiking my insulin levels too drastically. However, on race day or while training, high GI is preferred for fast energy.

On my heavier training days where the marathon workouts are longer and I have an additional strength session, I will be on the upper end of consumption in order to enhance recovery. On a lighter day that does not precede a hard workout, I will aim for 7 g/kg alongside 1-1.6g/kg of protein and healthy fats.

For those who train at altitude full-time or intermittently, protein is especially important as it aids in the formation of red blood cells. When training at higher elevations for a prolonged period of time or for Sunday long runs 2g/kg per day may be beneficial.

My pre-race my routine does not alter too much:

I will try to ingest the upper limit of carbohydrates before a race. I like to take some of this in the form of a fruit juice or sports drinks rather than heavy carbohydrate-dense foods.  I always consume a protein and healthy fat included the night before. Race morning is simple: oats and honey.

I have been lucky enough to work with Nuun Hydration for the last 18 months. This has been a game-changer. I hyper-hydrate 2 hours prior to my marathon by drinking 2-3 tabs in 20fl Oz of water to ensure that my electrolytes are topped up before the start. Hyper-hydration is not something I would practice daily but before a particularly hot or long workout, I will.

When deciding how many carbohydrates to take in during the race I used a breath analysis test at LEOMO to measure carbohydrate oxidation. This occurs when we burn carbohydrate for fuel.

During the race, I take 48 g of carbohydrates per hour in the form of Nuun Endurance which I mix with 24 oz of water. I aim to consume fluids ~5 km (~20 mins). This setup provides me with a perfect blend of fast-release energy and hydration in addition to topping off my electrolytes in order to eliminate the risk of cramps. I make sure to practice every new fueling strategy in each marathon buildup multiple times before race day.  Our team is notorious for placing random tables around the Boulder reservoir to practice our bottle pick up and fueling. Sorry if we’ve ever blocked your car!

After the race:

Ahhh! The time we can enjoy all the foods we have missed.

Personally, I struggle for many hours after a race or hard session to ingest solid food so I always opt for a smoothie. I blend 25 g of protein powder, almond milk, spinach, frozen berries, and a banana and aim to drink it as quickly as I can. Adding a frozen component can help to decrease your core temperature and aid recovery. This provides me with 50 g of carbohydrate and 25 g of protein (2:1 ratio) immediately. I then aim to eat a good source of antioxidants, fat, and protein to decrease inflammation within an hour.  Avocado, spinach, and eggs on toast was made for this.

In addition to quantity, the most important piece is figuring out which fuel will elicit the best response from your body. More carbohydrates can be digested when glucose and fructose are ingested together because they are absorbed via different routes in the intestine. However, some people have difficulty absorbing fructose. Like many ingredients in a sports drink fructose is a simple sugar known as a monosaccharide. However, if the cells on the surface of your intestines are unable to break down the fructose efficiently malabsorption occurs. Not only will your body struggle to absorb it efficiently, but you may also experience the dreaded “tempo tummy”. Nausea and headaches can also ensue. Surprisingly it affects 1 in 3 people.

If you have experienced any of these issues during training or racing it may be advisable to try some products which do not contain fructose.  Nuun Endurance is a non-fructose based equivalent. It’s very much a case of trial and error but beginning an informed self-study from day one of your build-up will give you the best shot of reaching the finish line feeling great.

For more info, please don’t hesitate to reach out: rosie@runcoach.com. Happy fueling!

Last modified on February 23, 2023
Rosie Edwards

Rosie Edwards

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