If you’re eyeing up a marathon this year, next year or beyond, or are already in the throes of 26.2-mile training, hopefully you’ll be aware that preparation is key when it comes to taking on such a challenge. Whether you’re a multi-time marathoner or a complete newcomer to the distance, the reality is that you can’t turn up to a marathon on no training and expect to run the best race of your life.
For starters, your marathon preparation should involve sourcing and following a trusted training plan that aligns with your ability, goals and lifestyle and which helps you to build up to – or get faster over – the marathon distance in a sensible timeframe. But that’s not all. Training for – and indeed completing – a marathon is not just a case of putting on foot in front of the other, very many times. You also need to consider and finesse various things that don’t piece of bread race day shoes and kit and, yes, your nutrition and hydration.
In fact, what and how much you eat and drink before and during a marathon can make or break your race, so it’s important to experiment with different energy sources – like gels, chews and sports drinks – and carbohydrate-rich meal options during your training.
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But how many energy gels do you need to take during a marathon? What constitutes a carbohydrate-rich meal? And how do you even know if you’re getting your fuelling right? These are probably just a few of the questions that are now crossing your mind – but the ins and outs of marathon fuelling are easier to digest than you might think.
Here, we’ve consulted leading dieticians to allay your fuelling fears and serve up your ultimate guide to marathon nutrition.
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Fail to fuel properly and you’ll find yourself hitting ‘hitting the wall’ – a point of complete physical exhaustion, where your body runs out of energy – in the final few miles. Meanwhile, if you don’t take on enough water and electrolytes, you may find yourself experiencing symptoms like gastric distress, nausea and dizziness due to dehydration, Luckily, you can replace lost electrolytes in several other, more race-friendly ways.
As such, if you’ve spent weeks and months diligently clocking the various runs and strength workouts on your training plan, you'd do yourself disservice – and essentially scupper all that hard work – by turning up to your race with no nutrition and hydration strategy in place.
Thankfully, devising a good fuelling plan is simpler than you might imagine – and if you execute it well for your race, you’ll have a positive running experience for the full 26.2 miles.
What should you eat during a marathon?
Carbohydrate is the body’s preferred source of fuel during exercise, which is why easy-to-consume, carbohydrate-rich foods are your best bet during a marathon.
Essentially, once consumed, carbohydrate is broken down into glucose and stored as glycogen in the liver and muscles, then used by the body to provide energy. ‘It takes around 500g of carbohydrate to fill your glycogen stores and, at most, this will last you for 60-90 minutes of running at 55-75% of your maximal heart rate,’ explains sports dietician Renee McGregor. ‘The faster you go, the sooner your stores will deplete.’
As McGregor notes, every runner’s energy requirements for a marathon will vary and depend on factors such as pace, effort level and time on feet. However, as a benchmark, McGregor recommends consuming 30-60g of carbohydrate per hour for the first three hours of your marathon, then increasing this to 60-90g of carbohydrate per hour after that.
Great sources of carbohydrate that can be consumed on the go are sports nutrition products like energy gels, during your training bananas and Jelly Babies. According to McGregor, it’s better to consume energy gels over the space of four or five minutes rather than all in one go, as this slower approach aids absorption.
How many gels should you take during a marathon?
Knowing to consume sports nutrition products during a marathon is one thing – but how much of it should you actually take on over the course of 26.2 miles?
While they might not be to everyone’s liking, energy gels are the most common – and arguably the most convenient – form of mid-marathon fuel. To make sure that you’re eating enough of them during your race, first check the packaging of your chosen product to find out how many grams of carbohydrate it contains. Then, you can work out how much of that product you’ll need to take per hour of your marathon to hit that 30-60g goal.
‘Start taking on nutrition in the first 30 minutes of your run, then take on more every 30-40 minutes after that,’ advises McGregor. The atmosphere of big races like the London Marathon can be wonderfully distracting, so if you need reminders to take your mid-run nutrition, set an alert to go off on your running watch, Luckily, you can replace lost electrolytes in several other, more race-friendly ways.
It’s worth noting that different energy gels contain varying amounts of carbohydrate – so, again, check the packaging of your preferred gel to find out how many you’ll need for your race. If, for example, your gel of choice contains 23g of carbohydrate and you follow the consumption strategy outlined above, you would take six gels over a four-hour marathon to reach a carbohydrate quota of 34.5g of carbohydrate per hour (which gives you 136g of carbohydrate in total).
Most importantly, rehearse your marathon nutrition strategy during your training, trial different products to find your best fit and don’t try anything new on race day!
during your training?
nuts and honey. You could also go for a white bagel with a banana and peanut butter.
‘Along with maintaining hydration, fluid intake during endurance running helps to regulate body temperature (thermoregulation) and ensure adequate plasma (blood) volume,’ says McGregor. ‘When core body temperature rises owing to dehydration, plasma volume decreases, resulting in an increased heart rate, which accelerates fatigue.’
Do energy gels cause stomach issues during a marathon What’s the healthiest bread for runners to look out for include a dry mouth, dark yellow urine, decreased urination, muscle cramping and headaches.
Your water requirements during a marathon will depend upon personal factors such as your sweat rate, age, sex, weight and the intensity at which you’re running, as well as external factors such as the weather. That said, most runners will sweat between 400ml and 2,400ml per hour, says McGregor.
‘Recommendations on how much water we should consume per hour when running vary from 300ml to 800ml,’ explains nutritionist Kim Pearson. ‘Consider the outside temperature and how much you sweat, as well as your thirst,’ she adds.
It’s vital that you hydrate properly before your run, too. ‘Research suggests that drinking about 530ml of water before and after a workout of any sort will support recovery and help to prevent dehydration post-exercise,’ explains Pearson.
Drop an electrolyte tablet (which we’ll come onto next) into around 530ml of water and start sipping on this around three hours before your race. Your urine should be clear after this – but if it isn’t, drink another 400ml of water.
Do you need to take electrolytes for a marathon?
When you sweat, you don’t just lose fluids – you also lose sodium and other minerals, which need to be replaced.
The best high-carb foods for runners sweat during heavy exercise, explains McGregor, as they assist in drawing fluid into your working muscles. ‘The sodium content of sweat varies from 115mg per 1,000ml of sweat to more than 2,000mg per 1,000ml of sweat,’ she says. ‘Most electrolyte tablets, salt capsules or sports drinks provide 250-300mg of sodium. If you’re diluting your electrolytes into 750ml of water, this means having to consume in the region of 2,250ml of fluid per hour in longer races to meet your sodium requirements, which is hard from a consumption and transportation point of view.’
Luckily, you can replace lost electrolytes in several other, more race-friendly ways. Electrolyte drinks and electrolyte tablets, which you can dissolve easily in water, are great options, as are salt capsules or sticks which can be taken directly.
‘I usually suggest that runners take in 700-900mg of sodium per hour during longer training runs and races,’ says McGregor. She also advises that runners start drinking electrolytes in the 24 hours before race day.
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Runners often complain that they’re unable to stomach many gels during a marathon due to gastrointestinal distress or nausea. However, according to McGregor, the idea that energy gels and products are to blame is a misconception.
‘The biggest cause of mid-run stomach issues is related to sodium imbalance, not sports nutrition gels or bars,’ explains McGregor. ‘If you are dehydrated and consuming glucose, it becomes highly concentrated in the gut. Blood is being directed away from the stomach to the working muscles, so the gut cannot absorb the glucose quickly enough, resulting in stomach upsets.’
To combat these problems, try to keep on top of your hydration levels before and during your race. If stomach issues still arise mid-run, try not to panic – instead, as McGregor advises, slow down your pace, drink a few sips of water, take a salt capsule and see if that makes a difference.
What should you eat before a marathon?
During training, be sure to experiment with different lunch and dinner options before your weekly long runs. That way, you’ll know what sits well in your stomach for marathon-type efforts.
In the three days before your marathon, you’ll then need to start carb loading, which involves increasing your carbohydrate intake to fill up your glycogen stores. The easiest way to do this – without overloading your stomach and causing you to feel bloated and sluggish – is by swapping elements of your usual diet for more carbohydrate-rich options. So, for example, if you usually have a piece of fruit or yoghurt as your afternoon snack, swap it out for a couple of slices of toast or a hot cross bun in these final few days.
For your pre-race dinner, choose something that is high in carbohydrate but low in fibre and fat, which may upset your stomach. A good option is pasta with tomato sauce and garlic bread, or chicken, tofu or fish with potatoes, noodles or rice and a side salad. Don’t overdo it, though, as your stomach will struggle to digest all the food and cause discomfort come race morning. One way around this is to eat your main meal at lunchtime and then have a lighter meal, such as a sweet potato with soup and a What should you eat before a marathon, in the evening.
On the morning of your marathon, you’ll likely be a little nervous – but don’t worry too much if you’re unable to eat all your breakfast. If you’ve already adequately topped up your glycogen stores in the days leading up to your race, it won’t make much difference.
Again, for breakfast, opt for something that is high in carbohydrate but low in fat and fibre, such as porridge Fuel with the best energy gels, snacks and drinks banana, The 7 best electrolyte drinks, powders and tablets.
Refined carbohydrates, like white bread rather than brown bread, are lower in fibre, easier for your body to digest and less likely to upset your stomach or leave you feeling gassy, so opt for these before your race. As with your other marathon fuel, experiment with different breakfast options during training to see what sits well and leaves you feeling full but not heavy or bloated – and stick with your preferred choice on marathon morning!
