In the quest for performance you'd think modern sport science would have been able to deliver a definitive answer as to what the best nutrition for trail running is by now. Unfortunately, it's quite complex and there is no single clear–cut answer. To maximise an athlete's performance, a nutrition plan needs to be tailored to the individual, the race they're targetting and the conditions. The intensity of the exercise, duration, weather, bodyweight and natural genetics are all factors that influence the nutritional needs of a runner.
Professional athletes work with qualified nutritionists to perfect their diet. For amateur runners, trying various gels, chews, drinks and foods during training and making small adjustments accordingly is a good substitute.
How Does Duration Affect Nutrition?
90 mins and Below
On a short/medium run your body uses glycogen (made from carbohydrates) as a fuel source for the first hour or so of exercise. You can replenish your glycogen levels as you go eating easily digestible energy gels and chews.
Energy gels and chews are made from Maltodextrin (Mn) rather that sucrose (sweets) or fructose (fruits). Mn gets broken down one molecule at a time rather than in big chunks as with sucrose/fructose. These big chunks of sugars can cause your gut to flood with water and give you an upset stomach.
You will find some fructose in energy drinks because when it's mixed with Mn it increases the rate of carbohydrates you can absorb. However the body can only take on 60g of functional carbohydrate per hour.
Above 90 mins
After two hours of exercise your body starts to move away from carbohydrates as its primary source of energy and begins to use fats and protein. You'll want to eat these as well as carbohydrates; replacing about 25% of the carbs with fats and protein.
Longer races require a less intense pace which gives you the time to effectively digest solid foods; making nut bars, flap jacks and high-energy snacks a viable option.
90 mins and below
- Water 0.5L – 1.1L and 200 - 300 calories of carbohydrates (energy gels/chews) per hour
If you are using a hydration pack take a gulp of water then spit it in to measuring jug. This way you know how many gulps you need to take to keep yourself hydrated. It's a good idea to test out different brands of energy gels, chews and liquid carbohydrate drinks and see how your stomach/body reacts, rather than trying something new on race day.
Above 90 mins
- Water 0.5L – 1.1L, 200 – 300 mg salts and electrolytes and 200 -300 calories of 75% carbohydrates 25% fats and protein per hour.
After your training session try a variety of protein-rich foods and recovery supplements till you find a combination that suits you.
In order to stockpile your glycogen stores, a high % of every meal you eat 24 hrs before the race should be carbohydrates (often referred to as carbo-loading). A common mistake is to try and eat all these carbs in one evening meal before the race. Your body cannot absorb them and they simply go to waste.
Breakfast before the race should again be carb heavy and could be porridge, toast or a little bit of fruit; around the 500 calorie mark. This should be consumed at least two hours before the start to give your body a chance to digest it.
During a Race
90 mins and below
- Water 0.5L – 1.1L and 200 -300 calories of carbohydrates (energy gels/chews) per hour
Above 90 mins
- Water 0.5L – 1.1L, 200 – 300 mg salts and electrolytes and 200 - 300 calories of 75% carbohydrates 25% fats and protein per hour.
Running can often supress your appetite and lead you not consume enough calories and nutrients. A useful way to ensure you keep up with your nutrition plan is to set an alarm on your watch for every 30 mins of the race as a reminder to eat.
After the race it's important to help your body recover as soon as possible. Studies suggest that a 30 minute delay in this can cause your body to initiate a stress response that slows muscle repair/carbohydrate intake. An easy fix for this is a recovery drink that contains carbohydrates (replenishing glycogen stores in your muscles) and electrolytes followed by a protein-rich meal to help repair muscles.
It helps to avoid inflammatory foods such as those containing trans/saturated fats. A small amount of low fat milk or ginger works well as an anti-inflammatory.
A final thing to consider is the stress and fatigue you have put on your body/mind which can leave you vulnerable to infection. This is a common problem for ultra-runners in the two weeks after a race. A slow release vitamin C supplement will boost your immune system, reducing the chance of this.