Ultra Marathon Nutrition Plan: What to Eat on Race Day

Reading Time: 6 minutes

An ultra marathon is long enough that what you eat matters as much as how you train. Over five, ten or twenty hours you use far more energy than your body can store, so you have to keep topping it up as you go, while you are moving, tired and often not hungry. This guide covers what to eat and drink the night before, on race morning, during the race and afterwards, including between stages of a multi-day race, and what to do when your stomach stops cooperating.

In short: on race day, aim for 60 to 90 grams of carbohydrate (250 to 350 calories) an hour, starting in the first 30 minutes and eaten little and often, with a mix of sweet and savoury food. Drink 400 to 700ml an hour, mostly to thirst and with some sodium, and practise all of it in training.

More people drop out of ultras because they stopped eating than because they stopped being fit. I see it at every event. Someone who trained for six months leaves at a checkpoint on 60km, not because their legs went but because their stomach did an hour earlier and they stopped putting anything in.

This is what I tell our runners about ultra running nutrition on race day. It is not complicated. It is just easy to get wrong when you are tired.

What to eat the night before and the morning of an ultra

Eat a normal-sized, carbohydrate-heavy dinner the night before. Pasta, rice, potatoes. Not a huge one, and nothing you have not eaten before. The point is a full glycogen store, not a full stomach.

Breakfast two to three hours before the start. Porridge, toast, a bagel, a banana. 400 to 600 calories, mostly carbs, low fibre, low fat. If the start is at 6am and you cannot face food at 3am, eat a bigger dinner and have something small on the walk to the line.

Drink 500ml with breakfast and then sip until the start. Do not down a litre in the pen.

What to eat during an ultra marathon

The target is 60 to 90 grams of carbohydrate an hour. For most people that is 250 to 350 calories. Start in the first 30 minutes, not when you feel hungry, because by the time you are hungry you are already behind.

The practical way to hit it is to eat something small every 20 to 30 minutes rather than a lot every hour. A gel, a few chews, half a bar, a handful of crisps, a cup of coke at the checkpoint. Mix sweet and savoury from the start. Everyone gets sick of gels by hour four and it is much harder to introduce savoury food once that has happened.

Use what you trained with, and carry it. What a checkpoint provides varies a lot between races. At our UK and European events there is a full table of sweet and savoury food. At the more remote ones, Jordan and South Africa among them, checkpoints provide water and nothing else, and you carry every calorie for the stage. The race information pack tells you which you are getting. Read it, plan around it, and treat anything on the checkpoint table as a bonus rather than the plan. If you have never eaten a jam sandwich on a run, 70km into a race is not the time to find out how it sits.

How much should you drink during an ultra?

Aim for 400 to 700ml an hour depending on heat and your own sweat rate, which you should have a rough idea of from weighing yourself before and after a few long training runs.

More is not better. Drinking plain water in large volumes over a long day dilutes your blood sodium, and hyponatraemia puts people in hospital at ultras every year. Thirst is a reasonable guide for most runners. Clear urine and a sloshing stomach are signs to ease off.

Electrolytes and salt tablets

You lose sodium in sweat, more in the heat, and some people lose a lot more than others. Over a long day you need to replace some of it.

For most runners that means an electrolyte drink or tabs in one of the bottles, plus salty food from checkpoints. Salt capsules work for heavy sweaters but take them with food and water, not on their own. The amount is individual, which is why this has to be tested in training and not worked out on the day.

If you have white salt marks on your kit after long runs, you are at the heavy end.

What to do when your stomach goes

It will, at some point, in a long enough race. The usual causes are going too hard, too much sugar at once, too much fluid at once, or heat.

What works:

• slow down for 20 minutes, walk if needed
• stop eating sweet things, try something plain and salty
• small sips of water rather than big gulps
• flat coke or ginger if the checkpoint has it
• keep moving, do not sit at a checkpoint waiting to feel better

Most stomachs come back within 30 to 45 minutes if you ease off. The mistake is to stop eating entirely because you feel sick and then bonk an hour later, which is worse.

When to use caffeine in an ultra

Useful, especially in the second half and at night. Two to three milligrams per kilo of bodyweight, roughly a strong coffee or two caffeine gels, from the halfway point onwards. If you drink a lot of coffee normally, cut back in the week before so it has an effect.

Do not start caffeine in the first hour of a long race. You want it when you need it.

Stage race nutrition: eating in camp between stages

In a multi-stage race the hour after you finish each day matters more than anything you eat on the course.

Eat within 30 to 60 minutes of crossing the line, even if you do not want to. Carbs and protein, something like a recovery drink, a sandwich, rice and chicken. Then a proper dinner two to three hours later. Then something before bed. Then breakfast. The deficit from a 40km day is large and you have to spend the whole afternoon and evening closing it.

Runners who skip the post-stage meal because they feel sick are the ones who start day three empty. In the heat this is the single most common way a stage race goes wrong.

After the race

Eat whatever you like. You have earned it. Then spend the next few days eating properly, sleeping and drinking, because the recovery from a stage race takes longer than most people allow for.

A sample race day nutrition plan for a 50km ultra

For a 50km trail race starting at 8am, something like:

• 5.30am: porridge, banana, coffee, 500ml water
• 8am: start with 1 litre of fluid, one bottle with electrolytes
• From 8.30am: a gel or chews every 30 minutes, sip every 10 to 15 minutes
• Checkpoints at 15km, 30km, 42km: refill, grab something salty, a cup of coke, eat it on the move
• From 25km: alternate sweet and savoury every half hour
• From 35km: caffeine gel
• Finish: recovery drink or a proper meal within the hour

Adjust up for heat and for distance, and if the info pack says water only at checkpoints, everything on that list goes in your pack. Practise the whole thing on at least two long runs.

Mistakes I see most

• Waiting until hungry to eat
• Only carrying gels
• Trying checkpoint food for the first time in the race
• Drinking to a schedule instead of to thirst in cool weather
• Skipping electrolytes in the heat
• Stopping eating when nauseous
• Sitting at a checkpoint for 20 minutes to “let it settle”
• Not eating after the stage in a multi-day race

Ultra marathon nutrition: the short version

Eat early, eat small, eat often, mix sweet and savoury, drink to thirst with some sodium, and practise all of it in training. That is the whole plan. The runners who finish ultras well are rarely the ones with the most sophisticated fuelling strategy. They are the ones who kept eating.

Fuelling at Ultra X races

Every Ultra X race information pack lists exactly what each checkpoint provides, from a full spread at the UK events to water only at Jordan and South Africa. Read it before you plan your fuelling, not the night before the race. Our nutrition partner is Science in Sport, and the Training Xone has a free ultra nutrition guide created with sports dietitian Renee McGregor. For the specifics of eating in the heat, see the desert ultra guide.

Frequently asked questions

How many calories do you need per hour in an ultra?

250 to 350 calories, or 60 to 90 grams of carbohydrate. More than that is hard to absorb while running.

What should you eat during an ultra marathon?

Something small every 20 to 30 minutes from the first half hour, adding up to 60 to 90 grams of carbohydrate an hour. Mix sweet and savoury from the start, such as gels, chews, half a bar, crisps and a cup of coke at checkpoints, and use foods you have tested in training.

What should you eat the morning of an ultra marathon?

400 to 600 calories of mostly carbohydrate, two to three hours before the start. Porridge, toast, a bagel.

Should you take salt tablets during an ultra?

Heavy sweaters and anyone racing in heat usually benefit. Take them with food and water and test the dose in training.

How much water should you drink during an ultra?

400 to 700ml an hour depending on heat and sweat rate. Drink to thirst and avoid large volumes of plain water with no sodium.

What do you do if you feel sick during an ultra?

Slow down, switch to plain salty food, take small sips, keep moving. Most stomachs recover in 30 to 45 minutes. Do not stop eating entirely.

How do you fuel a 100km ultra?

On the same principles as a 50km: 60 to 90 grams of carbohydrate an hour, little and often, mixing sweet and savoury and drinking to thirst with some sodium. Over a longer day, savoury food, caffeine from halfway and planning around what the checkpoints provide matter even more.

What should you eat after each stage of a multi-day race?

Carbs and protein within an hour, a full meal two to three hours later, something before bed and a proper breakfast. The deficit from a long day is bigger than one meal.