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Eating and Competing!

Part 2: Endurance Events

In the first part of this series we looked at how to fuel for a multi-event strength and conditioning competition, most popularly characterised by CrossFit comps. Now, we turn our attention to those of you who tackle endurance events – marathons, ultramarathons, half and full Ironmen, long cycling sportive and the like!

The longer and more intense the race, the greater the demand on your energy systems and body, and so the more important your nutrition and hydration strategy before, during and after. It doesn’t matter how good your training and nutrition plan has been in the lead up, if your nutrition and hydration is not on point on race day your performance will suffer … as will your post-race recovery.

Most of your power output in an endurance event will come from your aerobic energy system. The anaerobic systems will also be active, but their contribution is minimal. The primary fuel for the aerobic system, when available, is carbohydrate in the form of glucose from the blood and glycogen stored in the liver and muscle (which is why athletes seek to “carb load” to maximise their glycogen levels in advance of a race). Fat will be used to a greater or lesser degree depending on the availability of carbohydrates and the intensity and length of the event. The balance between using carbs versus fat to fuel the aerobic system is also dependent on an individual’s capacity and efficiency at fat utilisation, which is impacted by both genetics and training under conditions of carbohydrate deprivation.

This point around differences between athletes is a crucial one – every body is different, which means our optimal fuelling strategies are different. The right strategy for you will depend on the way you convert food to fuel, your efficiency at using different foods, and how the jiggling of exercise and nerves of race day impact your digestive system … we are talking the sensitive topic of gastro issues from either end!

Because a) the right nutrition and hydration is so important before and during endurance events and b) every athlete is different, it is vitally important you practice your pre-race day and race day nutrition in advance of the competition. You will have been undertaking long training sessions to prepare for the event, so this gives you lots of time to practice and perfect the feeding strategy that is likely to work best for you (subject to the additional race day anomalies that can sometimes plague even the most seasoned athletes!).

The tapering period

In the days and weeks leading up to race day, you will have tapered your training. This is likely to reduce the calories you burn each day, and so the number of calories you need to consume to maintain your bodyweight and lean mass. Despite this, in the final days leading up to the event you are also going to want to “carb load”, i.e. to maximise your muscle and liver glycogen stores so that you have as much stored carbohydrate as possible to fuel you on race day.

To maintain energy levels do not eat less than your estimated energy expenditure – if you are worried about the impact of reduced training on the number of calories you burn across a long taper, make a rough estimate and reduce your calories by this amount and monitor your weight and energy levels carefully. If your weight and energy falls, then increase your calories.

In the last 3-7 days before the race, increase the proportion of your calories coming from carbohydrates by 10-15%. Consider eating the majority of these soon after any training that you are doing, particularly if you are including HIIT in this period. This will maximise the glycogen stored in your muscles, ready for race day. For every molecule of glycogen stored, you also store 3 molecules of water – so if your weight increases slightly in this period, do not worry!

In this final 3-7 days you also want to ensure you are taking on sufficient salts (in particular sodium) to maintain your electrolyte balance and support optimal hydration on race day. If your primary fluid intake is water and other drinks that lack electrolytes, it is recommended that you eat salty food alongside.

If you are susceptible to gastro issues during your endurance training and events, you may want to consider tapering your fibre intake by up to 25% in the 2-3 days before the big race. Switch to “white” bread, rice and pasta and opt for low fibre fruit and veggies, such as aubergine, tomatoes, carrots, green beans, melon and peeled apricots and peaches.

The night before

As mentioned in part 1, the night before is similar for any sporting event and discipline … the name of the game is to fuel up!! Eat a meal that is high in carbohydrate (to continue glycogen loading) and with a moderate amount of protein to support a steady release of energy from the food consumed, and support muscle maintenance in the period before the race. Keep fat low to avoid slowing gastric emptying (food leaving the stomach!) too much and potentially leaving you feeling sluggish on race day.

Typical ‘night before’ meals include:

· Spaghetti Bolognese

· Chicken, rice and avocado

· Baked potato, butter and baked beans

· Pizza, with just a little cheese (yes really!)

All with added salt, and taken with at least a large glass or two of water.

The morning of race day

If you have eaten and tapered your training appropriately in the days and weeks leading up to the event, you shouldn’t need to use the morning of race day to seriously fuel. It should serve to top up your glycogen and blood glucose stores and keep you from feeling hungry as you approach and cross the start line!

Assuming your race begins in the morning, 2-4 hours before aim to eat a breakfast containing 2.5g carbohydrate per kg bodyweight. These should be low glycaemic index to sustain blood sugar levels without spiking them. For this reason, a moderate amount of protein should also be consumed. Fat should be low so as not to slow gastric emptying … you don’t want a full stomach on the start line!! If you are eating breakfast more than 4 hours before the start of the race, it is recommended to have a smaller high carb, moderate protein and low fat top up snack 2 hours before the event.

Up to 50% of endurance athletes have reported gastro issues in one or more of their events (nerves plus jostled insides as you move!). If you are susceptible to, or worried about this, consume a liquid meal.

Typical ‘morning of’ meals include:

· Large bowl of oatmeal made with skimmed milk and a pinch of salt, topped with banana and a large spoon of high protein yoghurt

· Toast topped with high protein low fat yoghurt, avocado and salt

· Smoothie made with oats, whey, banana and skimmed milk, and a pinch of salt

Taken with at least a large glass or two of water.

Many endurance athletes take a large coffee with breakfast, or up to 30 mins before the start of the race. Caffeine is possibly the most popular ergogenic aid amongst athletes. Caffeine sensitivity differs extensively between individuals and so test dosages in advance … if you get jittery, you have probably taken too much! Sports council recommendations typically start at 2mg per kg bodyweight, up to 5-6mg per kg bodyweight. A typical cup of filter coffee contains around 80-90mg, to give you a rough indicator of what you may be taking in. And contrary to popular belief, coffee is not a dehydrator!!

During the event

First and foremost an athlete must hydrate effectively! Athletes should drink before they feel thirsty – typically thirst kicks in when you are 1-2% dehydrated, by which point mental capacity and athletic performance is already impaired. In short, start sipping from the outset! Aim to consume 100-250ml every 15 mins, and you should be needing to pee every 2 hours or so … and it shouldn’t be dark in colour when you do so!! If it is, or it has been 4 hours and you haven’t stopped yet, drink more!!

Important to remember – water is not the way to hydrate!! Due to the loss of salts in sweat and the use of salts in the body, drinking water alone increases the risk of hyponatraemia. This is where the salt : water ratio in the blood is too low, with consequences ranging from nausea and dizziness to coma and death! The longer and more intense the event, and so the more an athlete sweats, the higher the risk. To reduce the risk of hyponatraemia, athletes should hydrate with a balanced electrolyte sports drinks. These can be purchased, or an athlete can make their own. Typical guidelines are 350-450 mg sodium plus 3-4% sugars per 500ml of water.

If you have loaded your glycogen stores appropriately before the race you should have enough to sustain you for up to 2 hours of moderate to intense exercise. Having said this, you want to start in event eating before you exhaust these supplies and “hit the wall!”!!

For events lasting over an hour, the guidelines are to consume 40-90g high glycaemic index (i.e. rapidly reach your blood as sugar!) carbohydrates per hour, starting after the first hour of the event. This is most easily taken in small increments every 15-20 min intervals to avoid filling their stomach too much at any one point in time, which can slow you down as blood is diverted from your muscles to your gut for digestion and / or cause stomach cramps as insufficient blood is diverted to your stomach to aid digestion because it is needed by your muscles!

Play with the amount of carbs you consume during training – every body is different, and a 105kg man is likely to need something quite different to a 65kg woman, for example!! Also play with the type of carbs you consume – it can be helpful to eat a combination of different simple carbs as they are each digested and absorbed at a slightly different speed, helping sustain energy and prevent the gut being flooded with all you have ingested at a single point in time … which would increase the risk of gastro issues! It can also be helpful to avoid consuming too high a proportion of fructose, which can upset your water balance increasing the risk of dehydration.

Some athletes also find it beneficial to consume a little fast digesting protein alongside their carbohydrate, for example whey powder or oat based snacks. In endurance events protein can provide 5-10% of the fuel for the aerobic system, particularly if an athlete gets into a situation of low energy levels. Providing protein as a food source can reduce the risk of muscle breakdown to supply the protein fuel.

Whether your feed on solids or liquids, and what sorts of solids or liquids, during events to get your carbs and (potentially) protein is a matter of personal preference. Some people find carb loaded sports drinks work best for them, whereas others prefer to chew a small jam sandwich!! The type of endurance event you do will of course also impact what is easiest to take on board … it is slightly easier to eat a flapjack on a bike than it is as you run or swim, for example!!!


When the event is over, appropriate fuelling isn’t!! You need to ensure you refuel to replenish your muscle and liver energy stores, give your muscles the protein they need for repair, and your body the micronutrients it needs to recover and ward off sickness.

Within 60 minutes of completing the event it is recommended to consume 1g carbohydrate per kg bodyweight, and somewhere 25-40g of protein – the more muscle you have and the more of your muscles that are involved in your sport, the higher the optimal protein dose. Aim for a high glycaemic index carbohydrate such as glucose (it is recommended to avoid taking in too much fructose at this point, which can impact water uptake and exacerbate dehydration), and a fast digesting protein such as whey or whey hydrolysate. Many athletes will drink a whey protein shake made with skim milk, or with added sugar.

As with a CrossFit competition, you then want to follow this with a meal rich in protein, complex carbohydrates and fats within 2-4 hours of completing the event. Try and ensure this is also rich in micronutrients, including antioxidants, to support your body’s repair and recovery post competition (see my blog on sports nutrition for those micronutrients that are of particular importance to athletes) – a number of key minerals are lost in sweat, so even if you were tip top in vitamins and minerals pre-event, the amount used plus lost can mean you’re crying out for them post event!! In all seriousness – a burger, chunky chips (reducing the fat:carb ratio) and a side of salad is a great refuel!!

After that first meal, ensure you continue to eat balanced micronutrient rich meals of complex carbohydrates, protein and fats regularly across the next 48 hours to support your body’s repair and recovery. If you tapered your fibre intake in the days leading up to the event, reintroduce it just as slowly to avoid gastro pain and upset, particularly as your body is already sensitive after the stress of the competition!


Appropriate nutrition and hydration is VITAL to enabling you to perform to your best in endurance events. Get it wrong and your performance will be impacted. The key is to take in enough to fuel you and not too much to slow you down, or worse. It is a fine tightrope!! Every body is different, meaning it is vital you practice your race day nutrition in your training sessions to figure out what works best for you – take the general principles outlined here and in the further reading referenced below, and tweak it until you have something that sees you moving faster than ever to smash those PBs on competition day!!

Further Reading …

McArdle, W, Katch, F, Katch, V. Exercise Physiology, Energy, Nutrition and Human Performance. 8th Edition. Wolters Kluwer Health, Philadelphia, USA. 2015.

Wilmore, JH, Costill, DL. Physiology of Sport and Exercise. 3rd Edition. Human Kinetics Publishing. 2005.

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