Whether you are training for a marathon or any other endurance event this season, you’ll need to have a well-rehearsed fuelling and hydration plan if you want to perform to your best ability and avoid nutrition mishaps.
The most common nutrition challenges you’ll face when training for a marathon include dehydration, overhydration, running out of energy, overheating, cramping and gut problems. With this in mind, here are some simple tips to help you avoid these common nutrition pitfalls.
Fuelling training runs
Training runs can be useful for practicing your race nutrition. Trial different foods and drinks, amounts and timings during training to pinpoint what works for you (and what doesn’t). Doing this will help avoid gut problems on race day.
Carbohydrates deliver energy to muscles faster than fats but are stored in much smaller amounts – about 500g, not enough to fuel 26.2 miles – so you’ll need to top up blood glucose with carbs at regular intervals during long runs.
Many runners prefer doing their long runs early in the morning, especially at the weekend. If this is you, then prioritise carbs in your meals the day before to ensure you have plenty of glycogen in your muscles. Its fine to skip breakfast if you want, but have a small pre-run snack 15- 30 minutes before you set off – good options include a banana, a slice of toast or a bagel with honey or peanut butter.
If you find it hard to eat solid food before your run, try a sports drink, diluted fruit juice or a smoothie – this will ensure hydration as well as carbs to maintain blood glucose levels.
Practice makes perfect
Aim to do two or three long runs using the same fuelling schedule you plan to use in the race. Simulate race-day conditions as far as possible, using the same foods and drinks and practise taking them at the frequency you anticipate during the race. Making it as realistic as possible will help ensure there won’t be any surprises on race day.
You’ll also need to practise drinking on the move from cups or bottles. This may feel tricky or uncomfortable if you’re not used to it so start with small amounts and gradually build up. Check in advance what’s available on the course and where the water stations will be so you can practice with the same products (if you want to) and plan where to refuel.
Whichever carbs and drinks you choose, start fuelling 45 – 60 minutes into your run. Aim for 30g carbs / hour if you’re anticipating a finish time > 4 hours; 60g/ h for a < 4-hour finish time or 90g/ h for a < 3 hour finish time. Good options that serve up 30g of carbs include one large banana, 500ml of an isotonic sports drink, one fruit + nut bar, or two Medjool dates.
2 – 3 days before the race
In order to start the race with a full tank of fuel, you’ll need to increase high-carb foods in the days before the race. This is called ‘carb-loading’ and can be achieved by a training taper for 2 – 3 weeks leading up to the race together with an increase in carbohydrate intake for the final 2 – 3 days. Good sources of carbs include oats, rice, potatoes, sweet potatoes and pasta. Fat and protein should be reduced to allow for an increase in carbs.
However, carb-loading doesn’t mean eating as much as possible. If you over-load, then you risk feeling bloated and lethargic on race day. If you are prone to gut problems, then you may wish to limit your intake of fibre during the 48 hours before the race.
The day before the race
Make your last big meal at lunchtime, not late in the evening, then a smaller meal at least 2 -3 before bedtime. This will ensure enough time to digest your food, so you won’t feel bloated on the morning of the race. Good options include a simple pasta dish, rice with chicken or beans or jacket potato with hummus or tuna. Avoid any new or untried foods or food combinations in case they upset your stomach.
The morning of the race
Aim to have your pre-race meal 2 – 4 hours before the event. The aim is to top-up carbs to ensure your liver glycogen stores are full before the start. Porridge or overnight oats with bananas, granola with fruit, or toast with jam are all great options. Stick to what you normally eat before a long run, nothing new. Drink plenty of fluid to ensure you are hydrated (your urine should be pale yellow), then sip as needed.
15 – 30 minutes before the start
If you skipped your pre-race breakfast or feel hungry, then consuming carbs shortly before the start will provide energy for the first part of the race. However, this is not essential. Aim for 20 – 30 g carbs with water – this could be a banana, sports drink or bar.
During the race
Replicate the strategy you have built during your training runs. However, be prepared to adapt if conditions change. For example, if it is hotter than expected, you’ll need to drink more; if gut problems arise, then you may need to cut back on carbs. Remember, don’t try any new products on race day in case they don’t agree with you.
After the race
Ensure you rehydrate over the next few hours by drinking water or sports drinks. Eat plenty of carbs and protein to aid muscle recovery – plus some fruit or veg for their antioxidant benefits. Once you’ve done that then, provided you’re not planning on running another marathon the next day you’re free to eat whatever you fancy!
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With less than three weeks to go before the 2021 London Marathon, here are nine evidence-backed nutrition tips to help you get the most out of your marathon training.
ALWAYS EAT CARBS PRIOR TO A LONG RUN
A good rule of thumb is to eat a good source of carbohydrate with a smaller amount of protein and healthy (unsaturated) fat two to four hours before a run. This combination of macronutrients will provide sustained energy to help you through a longer run. For long runs, avoid too much fibre within 30 minutes of exercise, especially if you are prone to tummy issues.
The carbs in your pre-run meal will help maintain blood sugar levels during your run and prevent fatigue, while a small amount of protein and unsaturated fat will slow the digestion of carbs, resulting in a more sustained rise in blood sugar – exactly what you need when running. Good pre-run meals include a jacket potato with beans, cheese or tuna; rice with beans; chicken stew with couscous; or pasta with tomato sauce.
THINK ABOUT THE NIGHT BEFORE
Many runners prefer doing their long runs early in the morning, especially on the weekend. If this is you, prioritise carbs in your meals the day before to ensure you have plenty of glycogen in your muscles. Then have a small pre-run snack 30-60 minutes before you set off – good options include a banana, a handful of dried fruit, or a couple of Medjool dates. If you cannot stomach anything before your run, ensure you’re properly hydrated before you set off and plan to run for less than 90 minutes.
REFUEL AS YOU RUN
For any run or race longer than 60-90 minutes, it’s worth thinking about taking extra carbs on board while you run. This will help maintain blood glucose levels and supply a quick source of energy to your muscles, which means you’ll be able to keep up your pace for longer. Start fuelling 30-45 minutes into your run and don’t wait until you’re depleted. Aim for 15-30g of carbs every 30 minutes depending on your pace; the key is little and often. Good options that serve up 30g of carbs include one large banana, one 50g energy gel, 500ml isotonic sports drink, or two Medjool dates.
DON’T FORGET ABOUT PROTEIN
There are three main goals of nutrition recovery: rehydrate, refuel and repair. Your post-run meal needs to supply carbs to replace glycogen but also protein to repair muscle. Aim for around 20-25g of protein post-run. Milk and soya milk alternative are near-perfect recovery drinks as they not only aid rehydration but also contain carbs and good-quality proteins to promote rapid post-run recovery. Great recovery meal options include a berry, yoghurt and almond smoothie; falafel and hummus wrap; chicken and prawn paella; bean and sweet potato curry; or a lentil, chickpea and cauliflower dahl.
MAKE SURE YOU EAT ENOUGH
One of the most common mistakes I see runners make when training for a marathon is under-fuelling. Marathon training should never be seen as a way to lose weight. Running long distances places a great deal of stress on the body and doing this without adequate fuel can harm your body. A consistent mismatch between your energy intake and output will almost certainly result in chronic fatigue, frequent illnesses and injuries and poor recovery. It can cause women to lose their period, which increases the risk of bone loss and stress fractures. Prevent under-fuelling by fuelling for the work required, ensuring you eat more carbs before hard sessions, and prioritising your post-run recovery nutrition.
CARB UP BEFORE A MARATHON
Carb loading – maximising your glycogen stores – may help delay fatigue and reduce your chances of hitting the dreaded wall. You can achieve this by increasing your carbohydrate intake for the final two days as well as tapering your training. This allows the carbs that you would have burned in your long runs to get stored as glycogen in your muscles instead. Don’t overload, though – aim to keep overall calories the same by cutting fat while upping carbs. Opt for easy-to-digest carbs (e.g. potatoes, rice and pasta), aim to eat most of your carbs at breakfast and lunch and avoid too much fibre.
MAKE A FUEL PLAN
Everyone’s different so you will need to work out what works for you by practising your fuelling and hydration strategy a few times during your long runs. Simulate race-day conditions as far as possible, using the same foods and drinks and practise taking them at the frequency you plan to during the race. Making it as realistic as possible will help ensure there won’t be any surprises on the big day. You’ll also need to practise drinking on the move from cups or bottles. This may feel tricky or uncomfortable to start with but start with small amounts and gradually build up. Check in advance where feeding and drinks stations are on the route so you can plan when to refuel.
STICK TO WHAT YOU KNOW
It may sound obvious but don’t do anything new on race day. I’ve seen so many first-timers make the mistake of consuming energy gels or products for the first time during their marathon experience stomach problems. If you want to use these products, trial them during your long runs. Similarly, don’t make the mistake of eating anything different for breakfast on race day – if you normally have porridge with honey before your long runs then eat porridge with honey before your marathon.
DON’T OVER-HYDRATE
If you’ve practiced a drinking strategy in training, then you should have a good idea how much to drink. But if the temperature is higher or lower on race day then you will need to adjust your plan. Dehydration can increase fatigue, slow your pace and cause a drop in performance. Equally, drinking more than you’ve lost in sweat – over-hydration – can be just as harmful. If you feel bloated, swollen and fatigued, then you’re probably over-hydrated so should stop drinking.
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Periodised carbohydrate training has become the latest buzzword among endurance athletes. Essentially it means matching your diet to your workload and new research suggests it may improve endurance performance and make you a more efficient fat burner.
The idea behind training with low glycogen stores (‘training low’) is that it forces the muscles to burn more fat for fuel and rely less on carbohydrate. By teaching your body to tap into its fat stores, you should in theory be able to keep exercising for longer before reaching fatigue.
Indeed, studies (here and here) have shown that when you ‘train low’ you increase the muscle’s adaptive response to training. It increases mitochondrial biogenesis, so you get an increase in the number and volume of mitochondria – the fat-burning powerhouses – in the muscle cells. The more mitochondria you possess, the greater your muscles’ ability to use fat as fuel, sparing your glycogen stores.
High-intensity exercise feels much harder. Your performance, rather than improving, may drop. Your immune system may become depressed, increasing the risk of infection. And you could lose muscle.
But with periodised carbohydrate training you get the dual benefits of ‘training low’ – namely fat adaptation – as well as the performance benefits of high intensity training. Also, it’s a more sustainable approach. Essentially, it means doing some of your low-intensity sessions in a carb-depleted state, and your higher intensity sessions with high glycogen stores.
The simplest way to ‘train low’ is to train in the morning before breakfast. However, this should be done before an easy session, nothing too long or too intense. Alternatively, if you want to train low in the evening, cut carbohydrate at breakfast and lunchtime (keeping to mainly high-protein foods and vegetables). Another method is ‘sleeping low’. This means doing a tough session before sleep, eating a low carb dinner then doing a low-intensity session the next morning.
This method looks more promising in terms of performance improvement. A multi-centre 2016 study with triathletes found that those who followed a ‘sleeping low’ protocol for three weeks improved their cycling efficiency (power output per calorie) by 11%, 10km running performance by 2.9%, time to exhaustion during high intensity exercise by 12.5%, and also reduced their body fat compared with those who did all their training with high glycogen stores.
A follow-up study with cyclists by the same team found that using a ‘sleeping low’ strategy for just six days resulted in a 3.2 percent improvement in a 20K time trial.
Most recently, a study at the Australian Institute of Sport compared the performance effects of a high-carb diet (60 – 65% carb), a periodised carb diet (same macro’s but periodised within or between days) and a LCHF diet (<50g carbs) in a group of 21 elite race-walkers. After 3-weeks on each diet, all athletes improved their aerobic fitness (VO2 max) but only those on the high carb or periodised carb diet improved their 10k race performance. The athletes on the LCHF diet did not make any improvement. Although they were burning a higher proportion of fat during exercise, their muscles became less efficient at producing energy, requiring more oxygen at any given speed. All of which suggests that fat adaptation incurs an efficiency penalty.
To date, this is the highest quality study on low carb vs high carb that we have. Although It makes a pretty damning case against chronic low carb diets, it also provides good evidence for a periodised carbohydrate approach.
In summary, eating low carb all the time is unlikely to benefit your performance unless you’re exercising at a relatively low intensity for long periods, such as ultra-distance events. For other endurance activities, it may be worth trying a periodised low carb approach.
Pick just one or two short low-intensity sessions a week alongside your normal training when you are fully fuelled. Keep a training log and see whether it helps your training or not. If you suffer gut problems when consuming carbs during running, then ‘training low’ may suit you. Also, not having to carry bars and gels during long runs may be helpful from a practical point of view. Remember, whatever the research says, a good nutrition strategy boils down to doing whatever works for you as an individual.
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The Complete Guide to Sports Nutrition, ninth edition is the definitive practical handbook for anyone wanting a performance advantage. This fully updated and revised edition includes guidance on:
If you enjoyed this article and want to find out more about food and nutrition, as well as some easy and tasty meal inspiration, then my new book, 
More than 100 delicious, easy-to-prepare vegetarian and vegan recipes for healthy breakfasts, main meals, desserts, sweet and savoury snacks and shakes.