Nutrition is key for performance, if we want to perform well, then we need to fuel well both in preparation and during our run. However, running nutrition can be challenging for most individuals, no matter how experienced! It can take a long time to work out the best strategy for you and it will likely change depending on the distance you’re running, there is truly no one size fits all approach! As a runner, most have experienced a time when running where our stomach has become uncomfortable. Not only can it really take the enjoyment out of running, it can also make or break your session/event. If we follow a healthy balanced diet, we should have enough fuel to last us approximately 60-90 min of exercise. For the majority of individuals, carbohydrate is our bodies preferred fuel choice. By consuming carbohydrates during running our body is able to maintain blood glucose levels which can then help postpone fatigue and spare our muscle glycogen (the storage form of carbohydrates in our muscles) stores, therefore allowing us to exercise for longer. If when we run we become dehydrated, this can also result in stomach issues. As well as this, maintaining hydration is key to regulating body temperature and plasma (blood) volume, both of which will impact performance. If our plasma volume decreases due to dehydration, our heart has to work harder meaning we have an increased heart rate, leading to fast-tracked fatigue. To find out more about the importance of hydration and electrolytes see here, but overall as runners, we need to find this unique balance of consuming enough carbohydrate and staying hydrated to perform optimally whilst also hopefully avoiding any stomach issues. So how should I fuel my session? When it comes to running nutrition, individual preferences will have a large effect. This is due to differences in gut health, taste preferences and need according to our body weight and sweat rate. A lot will also come down to exercise duration and intensity. The chart below is taken from our design your own fuel strategy article which can be found here. It’s designed to help you decide how many grams of carbohydrate per hour you should aim for depending on the duration and intensity of your run. Effort level Carbohydrate recommendation in g per hour Hard 0 30-60 30-60 60-90 80-120 80-120 Moderate 0 0 30-60 30-60 60-90 80-120 Easy 0 0 0 30-60 30-60 60-90 30 min 60 min 90 min 2 hr 2.5 hr 3 hr + What’s easy? – You’ll be able to breathe normally throughout What’s moderate? – Your breathing is more laboured, but you’re still fairly comfortable What’s hard? – You’ll be breathing heavily and it will feel pretty uncomfortable Some of these amounts of carbohydrate may seem like a very large amount, it would take time to build up to these amounts so your body can adapt, similar to how you would build up your running distances so your muscles and cardiovascular endurance can develop, your gut also needs training. Lighter athletes should also aim for the lower end of these recommendations. You can fuel your run with a variety of food and/or energy supplements depending on your preferences, a popular option amongst runners are our GO Isotonic Energy gels! A lot will come down to your personal preferences on taste and texture but you should also take into account the type of carbohydrate. If you want to consume more than 60g of carbohydrate per hour you should look to consume multiple types of carbohydrate such as glucose and fructose. This is due to different carbohydrate types having different transporters to carry the carbohydrate from the gut to the blood and these become saturated at certain amounts. For example, the maximum amount of glucose we can absorb is 60g per hour, so if we want to consume more than this per hour, we would need another type of carbohydrate such as fructose. Our Beta Fuel range is designed to provide the optimal ratio of glucose and fructose. Using Beta Fuel, it has been scientifically proven that consuming up to 120g of carbohydrate per hour is possible and well tolerated in terms of gastrointestinal issues. You can read more about how to fuel running with our Beta Fuel range here. Common fuelling errors It will always take a bit of trial and error to figure out what works best for you, but there are some common errors you can try to avoid. Becoming dehydrated and not replacing fluids and electrolytes. Becoming dehydrated by even 2% is enough to impact performance. Fuelling too late. Start taking on nutrition within the first 30-45 minutes if you know you’re going to need it later on to give your body time to absorb and digest. Trying new nutrition/fluids on the day of a running event. Golden rule in sport nutrition = nothing new on race day! How to I carry my fuel? During training, we will always have to rely on ourselves for our nutrition and hydration, unlike in a race where we often have manned aid stations throwing whatever we desire at us every couple of miles (which is great so thank you to all the volunteers at events that make that happen!). So how can we carry our nutrition and/or hydration? There are a few different options you can try and finding what works for you is important. Hydration backpacks are great for those longer runs on road or trail and they will often have additional pockets for things such as your phone or importantly your carbohydrate source of choice! For those who don’t like something on their chest, running belts are often a good option though don’t usually carry as much – they can have mini water bottles attached and pockets for nutrition. Other options include handheld water bottles which are useful for shorter runs but for longer they may not carry enough. Some running clothing may also incorporate pockets wither in a jacket, leggings or for the ladies out there, some sports bras can have integrated pockets all of which again can be handy for carrying nutrition. The SIS energy gels are designed to fit easily into pockets and being thin in design means they also fit in running belts and hydration backpacks well too! Finally, you could create your own aid station. Essentially, somewhere safe you can leave your nutrition and hydration (often on your doorstep would be a good option) but keep in mind you have to have the will power to continue with your run and not feel tempted to just finish there! So this option might not work for everyone. If you find a solution that works for you, you can also then use it in an event if you don’t want to rely on aid stations. If you are going to use the aid stations, try to find out in advance (usually this information should be available in the event guide) what nutrition will be available on the course so you can practice using that nutrition/hydration before the event. Ideally, we don’t want to try anything new on race day! Take home messages: Individuality is very important when it comes to running nutrition, just because it works for your running buddy or an Olympic runner, it may not work for you. Carbohydrate intake and hydration are both important for running, both should be considered for both training and competition. The important thing to consider is simply that you are fuelling for work required! Make sure you carry enough nutrition/hydration to perform optimally. Written By Dr Emily Jevons - PhD in Exercise Physiology & Nutrition, Clean Sport Advisor Emily has worked with Science in Sport since 2021. With a PhD in Exercise Physiology & Nutrition, she currently provides nutritional advice for endurance athletes. Emily not only understands the science behind performance nutrition solutions, but also the physiological and psychological demands of sport after competing competitively in swimming and triathlon for a number of years.