Correct nutrition is vital for success on race day, but it is all too easy to overlook its importance during training. In many ways, the human body is similar to a high performance car – no matter how good the engine is, if you put poor quality food inside it, performance will suffer.
With any race distance, preparation is the key for a good training performance, including the capacity to train at the right intensity and to recover afterwards, are crucial if your preparations are going to go well. Consequently focussing on correct nutrition in the months and weeks before a race is crucial, and remains important even if you are simply training with no particular goal or race in mind.
Our diet consists of three main “macronutrients” – fat, protein and carbohydrate.
Fat is very “energy dense”, containing lots of calories, but unfortunately not the sort that provide energy at the rate needed for running at speeds that are much quicker than a slow jog.
Protein helps to repair damaged tissues and provide the “building blocks” for the body, but only has limited value as an energy provider.
Carbohydrate is vital for energy, since it converted into a substance called glycogen, and stored in the liver and muscle used as the main fuel for running.
Since our glycogen stores are sufficient to fuel most runs up to a distance of around 18 miles, the majority of training runs will not face an energy crisis due to a loss of glycogen – it is only when a run is longer than 18 miles that this can become an issue. But shorter runs over consecutive days can present a cumulative energy problem if sufficient carbohydrate is not eaten to aid recovery.
A 6 mile run will use around one third of available glycogen, so this will not impact on performance, but if stores are not refuelled properly afterwards, the next run will eat into energy stores still further. If this continues over days or even weeks, there will be a gradual decrease in glycogen caused by poor nutrition, not the length of the run, and eventually even the shortest of runs will feel hard and training will suffer.
Knowing the importance of carbohydrate for runners of all distances, and the importance of early refuel to capitalise on the heightened activity of glycogen synthase, the enzyme responsible for converting carbohydrate to glycogen, it is easy to understand the importance of a daily high carbohydrate diet for
runners who train regularly.
At the same time, it is important to be sensible, since eating too much of any food can cause weight to increase, if energy intake exceeds energy expenditure. A 6 mile run is likely to use around 700 calories for most people, so this needs to be factored in when judging the food quantities used for refuelling.
The supply of nutritional supplements for sports people has become a massive business, but I always recommend that “food comes first”, since there is no substitute for a good, high carbohydrate diet. Supplements can contain a range of ingredients, from carbohydrate to caffeine, and from amino acids to vitamins. As long as you have a good diet, a lot of money can be saved from not purchasing these supplements.
When coaching celebrity runners, I always emphasise the importance of diet to support training, but occasionally suggest a daily multivitamin with iron, simply for “insurance”, especially as race day gets closer. Iron is important as it is needed for the production of haemoglobin, the part of the blood that carries oxygen from the lungs to the muscles, which if low can result in a condition called anaemia. This can be a problem for all runners, but particularly so for females at specific times of their monthly cycle.
Nutrition provides fuel, and fuel is needed for energy. Supporting training and racing with the right nutritional strategy is therefore crucial for successful high quality training and racing performances.