It is well known that nutrition, alongside training, helps play a key role in helping to optimize running performance 

In recent years not only has there been  a distinct increase of awareness in nutrition and its benefits on performance, but also in the number of places to access this information. The aim of this article is to help dispel some of the nutrition myths and give some information  as a starting point to help improve your running performance.

Energy Intake

It is important to remember to fuel ourselves correctly, so that running performance is at its best. Current trendy messages are to restrict energy intake (mainly through restricting carbohydrate); however, if we wish to maximise our running performance, energy intake should not be restricted. When it comes to optimizing performance for a race we need to consider energy intake as part of the preparation.

An analogy I often use with athletes is if you are going on a long journey in the car, you wouldn’t fill the petrol tank a quarter or halfway, you fill it up – the same principal applies in endurance running. In order to optimize performance, we need to maximise our energy stores in order to sustain us on  our journey.


I was at a sports nutrition conference  recently and one of the speakers made a fantastic statement: “When it comes to performance, carbohydrates are king.” This is because carbohydrates are the preferred fuel source for both the brain and muscles. When we eat carbohydrate sources (pasta, rice, potatoes, bread) we store this as glycogen in both our liver and muscles.

Glycogen is essentially our carbohydrate fuel stores in the body, so that when we exercise, we have a readily available store of carbohydrate available to fuel our muscles. During endurance exercise, carbohydrates digest and absorb into the bloodstream faster than fat and protein, and can be used more efficiently to help fuel our run. Therefore consuming carbohydrate (drink, gel,  bar) during a prolonged run (in excess of 60mins) may aid in running performance.


When we exercise, we cause micro-tears in our muscle fibres and in order to optimally recover, protein is an important part of this process as it helps to repair these micro-tears and rebuild our muscles from exercise. Current research suggests that in order to promote optimal rebuilding of muscle protein should be consumed every three to four hours.

For an endurance athlete, guidelines for daily protein intake are 1.2g – 1.6g per kilogram of body weight. For example, if we take the median of these recommendations (1.4g) and you weigh 75kg, this would equate to a daily protein intake of 105g protein per day. Initially, this may sound like a lot; however, the example below shows how this could potentially be achieved in a day:



Fat is not a dirty word. It plays a number of key roles in the body in relation to exercise such as acting as an energy source and aiding the absorption of certain vitamins, therefore it should be considered in any nutritional strategy for endurance running. During prolonged endurance events (marathons, triathlons, Ironman), as our glycogen stores start to deplete, the body will turn to fat as an alternative energy source in order to sustain our performance.


Within the average male, there is enough stored fat to sustain running performance for 120 hours – so it is not an energy source to be neglected in our diets, however, as previously mentioned, the body’s ability to utilise fat as an energy source is only when carbohydrate stores are becoming depleted – carbohydrate is still the muscles’ preferred energy source.

From a recovery perspective, healthy sources of fat such as Omega-3 have shown to reduce inflammation and could potentially aid in the recovery process from exercise. Healthy sources of fat include foods such as unroasted/unsalted nuts and seeds, oily fish and avocado.


Vitamins and minerals are sometimes overlooked as part of the preparation to improve our running performance, but they can greatly aid running performance.

However, it is worth remembering that a greater intake of these vitamins and minerals does not equate to a greater running performance. Research indicates that athletes of all levels are able to meet their dietary requirements for micronutrients through eating a wide variety  of foods. Some of the vitamins and minerals that require some consideration for running performance include:

Vitamin D

There has been a large amount of hype around vitamin D in recent times, and it would appear as though some of this hype is warranted – with research indicating it plays a number of important roles in relation to bone health, immunity and muscle function. Vitamin D is found in small amounts in foods such as fortified dairy products but the main source of vitamin D is from direct sunlight, which is sometimes a challenge in the UK.


Iron plays an important role in transporting oxygen in the blood and muscle, therefore low intakes of iron could cause potential issues with performance. It isn’t uncommon for an athlete to suffer from a low iron status or deficiency (known as anaemia) but there is a greater risk for runners who deliberately restrict energy intake. Foods that are rich in iron include meats, fish and poultry, and leafy green vegetables. Vegetarians will need to plan their meals carefully to find alternative iron sources.

Women are also at risk because of increased iron requirements due to blood losses associated with their menstrual cycle; consuming iron-rich foods will help to reduce this risk.



Calcium plays a key role alongside vitamin D to maintain healthy bones. This is highly important, particularly during periods of high training due to the impact and stress being placed on the skeletal system while running. The best sources of calcium are dairy foods (including low fat varieties) such as milk, yoghurt and cheese.

However if you are unable to consume dairy products, there are a number of calcium-fortified foods available.



As with most elements in sports nutrition, hydration requires a personalised approach and should be experimented with to see what works. Hydration pre-, during and post-training/ competition needs to be considered as part of this process. As a starting point of hydration, we should aim to try and drink enough fluid to replace sweat losses so that the overall fluid deficit is no more than approximately 2 per cent loss of body mass (example: 1.5kg for a 75kg individual) from a session.

When exercises last longer than 60 minutes, athletes are advised to consume a source of carbohydrate that is absorbed into the blood quickly – which is where a sports drink is useful – anything less than 60 minutes, water is fine.


Overall, the nutrition guidance within this article is exactly this. Personalised, tailored nutrition strategies should be trialled individually to see what works for you as an individual, or alternatively advice should be sought from a practising, registered performance nutritionist or dietician.

Words: Chris Curtis