Mastering ultra running nutrition: essential tips for peak performance

What to eat and when to help you achieve ultra success.

“Ultra racing is all about 3 things: Strong gut, strong mind, strong legs. And my motto is, “don’t use any new fuel on race day,” says Elsey Davis, elite ultra runner, and prestigious mountain race winner and STYRKR athlete.

During an ultra race, your body requires constant nutrition and fuelling.

Races that exceed 6 hours might induce an energy deficit upwards of 7,000 calories [1], even with mid-race nutrition. 

Nutrition is not just about replacing those lost calories; it’s about eating the right foods, in the right quantities, and at the right times.

It’s a puzzle ultra runners have been trying to solve for years. And when you get it right, you’ll have your best race yet. 

This blog post is your ultimate guide to ultra-running nutrition. 

What you will learn:

• How to fuel and what to eat for ultra running 

• The importance of pre-race nutrition and hydration (48 hours before)

• Common nutrition mistakes to avoid for peak performance

What is the best nutrition for ultra running?

Ultra running nutrition varies from person to person. 

But there are energy and nutritional guidelines you can follow to achieve peak performance.

You will need to eat before and consistently during an ultra race to give your body enough energy to fuel your running.

Ultra running nutrition plan

The team at STYRKR have put together an ultra-running nutrition plan to help you fuel correctly and perform your best, whether it’s your first ultra or you’re a seasoned ultra endurance athlete.

Continue reading for a breakdown of what to eat and when.

Pre-race 

Similarly to a marathon, you want to eat more carbohydrates 48 hours before racing to increase available muscle glycogen stores.

Eat 10g/kg/bodyweight/day for 48 hours before an ultra race, with care taken to avoid gastrointestinal distress [2]. 

For an 80kg runner, that’s 800g of carbohydrates/day in the two days before racing.

Avoid unfamiliar foods when carb loading and drink plenty of water - this ensures the body can store excess carbohydrates as fuel. Electrolyte mixes like SLT07 also support hydration and help the body absorb carbohydrates properly. It may also reduce your risk of hyponatremia - this is when there is a low concentration of sodium in the blood.

On race day morning, try to get extra carbs by eating breakfast 2-3 hours before race start.

Eat the same breakfast you eat during training - now is not the time to try new foods.

During ultra run 

You need to eat and fuel during the race, whether you’re running a 50km ultra marathon or the Ultra Trail du Mont Blanc (UTMB).

Aim to get a minimum of 60-90g/carbs/hour - this will give your body the energy it needs.

BAR50 contains 50g of carbs, and GEL50 has 50g of carbs. That’s 100g of quick-to-digest carbs. 

If you’ve run a marathon or an ultra endurance event before and are used to eating 60-90g/carbs/hour, you may wish to try upwards of 100-120g. 

See how your gut responds to an increased carb intake during training and adjust as needed to help fuel your body for race day success. 

Below is a table with examples of what food to eat to meet the energy recommendations (per hour).  

Davis recommends practising eating carbs in condensed periods to stimulate a nauseous feeling, which you will get when running.

It’s important to continue eating when feeling sick or nauseous, otherwise you’ll fall behind on your nutritional needs.

Moreover, drinking lots of water without sodium can lead to hyponatremia, which can cause nausea. Take 400-800mg/hour of electrolytes to support proper hydration and use SLT+ for added sodium, great if you’re a salty sweater.

Using aid stations 

During most ultra-running events, you’ll find a variety of aid stations where you can stock up on food and fluids. UTMB, for example, has major aid stations and fluid aid stations, where you can stock up on water, cola, coffee, soup, and other fluids. Major aid stations include hot meals, snacks, chocolate, cheese, and more.

Davis chooses normal food at most aid stations ."Crackers that melt in your mouth and are salty to get some savoury in and coke." She also picks up spare gels and choose various gels or textures like BAR50 rice bar, incase something isn’t going down well.

If running with a support crew (this can be friends, family, sponsors, agents, coaches, etc.), they can hand you extra energy bars, gels, and other items you are less likely to find at aid stations. You don’t need to carry all of your food and hydration - you can stock up en route.

For example, Tom Joly, professional ultra endurance runner, STYRKR athlete, and 1st Brit to cross the finish line and finish in sixteenth place in the 2013 UTMB, says his coach will be supporting him for this year’s UTMB, but he’ll only see him every 3 to 6 hours. 

“There will be long stretches where I need to carry enough fuel, but I don’t want to be carrying too much weight. STYRKR products work well because you can get 50g of carbs from a gel or an energy bar, which is higher than other products I’ve tried.”

Post-ultra 

Your nutrition doesn’t stop once you cross the finish line. 

However, you can treat yourself. Davis’s go-to post-race meal is a greasy burger and fries. Try to eat a meal within 1-2 hours after finishing. If you can’t quite stomach a meal, try a recovery bar like BAR+, which contains 15g of protein to support muscle repair and 45g of carbohydrates to help replenish glycogen stores.

Drink plenty of water, add electrolytes if needed, and eat plenty of carbohydrates and protein in the following days to support your recovery.

Hydration strategy for ultra running 

“Absorption of nutrition changes, based on how hydrated you are, so it's important to keep drinking to maximise your carbohydrate input,” says Davis.

Aim for a minimum of 300-600ml/hour of water (more in the heat). How much fluid you need varies, so practise this in training before race day. 

You won’t need to carry all of your fluid for the entire race - you can refill your bottles at aid stations.

Electrolytes play an essential role in proper hydration. Water or other fluid without sodium and other electrolytes can cause a fluid imbalance, preventing proper hydration and negatively affecting carb absorption. 

Further, you may wish to use caffeine before a particularly tough section or at certain times during an ultra. You can use a product like GEL30 Caffeine for 30g of quick-digesting carbohydrates and 150mg of caffeine.

Ultra running nutrition mistakes to avoid 

If this is your first ultra, you will make mistakes. Whether you don’t eat enough carbohydrates or you didn’t practise your nutrition on your long runs, mistakes happen.

Here are some common ultra-running nutrition mistakes so that you can avoid them.

1. Not practising nutrition in training 

You need to train your gut by practising with the nutrition you’ll use in races in training.

Often, runners eat during their long runs, but on race day, they abandon their nutrition choices and try new foods, eat at different times, and continue without a plan.

By eating the same foods as you do in training (and in similar quantities), you train your gut to tolerate, absorb, and use carbohydrates as fuel to provide you with a steady stream of energy.

New or unfamiliar foods are more likely to cause stomach upset. It’s not what your body and gut are used to. 

Also, you should know that carbohydrates digest at different speeds. For example, rice bars and energy gels are quick-to-digest, giving you more energy to use quickly. Slow to digest carbohydrates, like oats or wholegrain bread give you a steadier fuel source over time.

Know what carb source you’re taking and when to improve your fuelling (and plan when to use it).

2. Not fuelling when you feel nauseous 

“If you feel sick, you’re not eating enough and fuelling enough,” says Davis. “Fuelling correctly will likely stop you from feeling sick during a race.”

And while eating when you feel sick or nauseous may feel backwards, your body needs fuel to perform at its best.

Not eating or fuelling when needed derails your nutrition, too.

It’s virtually impossible to play catch-up on your nutrition without sacrificing your race. Once you hit the wall, it’s very difficult to come back.

3. Using aid stations incorrectly

There’s only so much you can pack when running an ultra race.

“Many runners don’t take into consideration their pack weight. You want to be as light as possible while still carrying the essentials (especially food items you likely cannot get at aid stations),” explains Davis.

Water and other fluids are readily available at aid stations, as well as common snacks like pretzels, sweets, oranges, bananas, and other fruits.

Plan ahead of time to reduce your pack weight and have the fuel you need at the right time.

“My advice for aid station extra fuel is, don’t overcomplicate it - if you have lots of options, your brain gets tired. Just keep it simple. Don't try and think about what you’ll want at aid stations, as the likelihood is you won't want anything, particularly at high altitude,” says Davis. 

Joly also mentions that he sticks to consistent foods and tries not to veer away from those if possible. “If you’ve been eating gels and foods you are used to, then you eat two bananas and cheese and crackers, that’s a lot of different food mixing around in your stomach. I often find that problematic.” 

4. Not adjusting nutrition to meet the climate 

Failure to adjust your nutrition to meet the race and environmental conditions is a quick way to derail your ultra.

Hot climates increase sweat loss, so you’ll need more fluid and electrolytes, like sodium.

In last year’s UTMB, Joly tells STYRKR how he lost a lot more salt and sweat than he was expecting, which caused cramping and fatigue. This year, he’s using SLT+, which has over 1000mg of sodium and other electrolytes for when the temperature increases and the sweat pours.

Colder conditions may require more calories for increased energy.

Adjust your nutrition as needed to reduce your risk of bonking, dehydration, stomach issues, and more.

FAQs

Why do ultra-marathon runners drink Coke?

Ultra marathon runners drink because it contains simple sugars for a quick energy boost. It also has a little caffeine and may help calm a queasy stomach.

How many gels for an ultra-marathon?

If you were only taking gels, you would need 2-4 energy gels/hour.

What to eat during a 50k ultra?

For a 50k ultra running race, you want easy-to-digest foods that are easy on the stomach. Rice bars, energy gels, chews, bananas, salty snacks, boiled potatoes, and carbohydrate-rich drinks are great options.

References:

1. Nikolaidis, P.T., Veniamakis, E., Rosemann, T. and Knechtle, B., 2018. Nutrition in ultra-endurance: State of the art. Nutrients, 10(12), p.1995.

2. Tiller, N.B., Roberts, J.D., Beasley, L., Chapman, S., Pinto, J.M., Smith, L., Wiffin, M., Russell, M., Sparks, S.A., Duckworth, L. and O’Hara, J., 2019. International Society of Sports Nutrition Position Stand: nutritional considerations for single-stage ultra-marathon training and racing. Journal of the International Society of Sports Nutrition, 16(1), p.50.