“Managing your nutrition throughout your training is essential to meet the growing energy needs as you increase your distance and to help avoid any injuries or illnesses that may de-rail your plans for race day,” explains Brown. “During training you'll need to be consuming around 4-6g per kg of body weight of carbohydrate.  This includes the fuel that you should be taking on while running around 30-60g of carbohydrate per hour – gels are really useful for this.  As you get closer to your event your carbohydrate intake should go up from around 60% of your diet to around 80% in the three days immediately prior to the race.
“Make sure that you do your experimentation with diet and supplements (gels and sports drinks) during your training so that on the actual race day your body's familiar with your routine. This includes your marathon-eve dinner and breakfast on the day itself.  Eating refined foods – white pasta, white rice, potatoes or bread the evening before your race and for breakfast on the day itself will help make sure your energy stores are fully topped up, and will help avoid any potential digestive problems that a fat or fibre rich meal could cause. 
“During the race, make sure you know where the water stations are and make full use of them! You should have practiced your hydration strategy during your training so you should know when and how much you need, and when to supplement with electrolytes or a gel to keep your energy and electrolytes balanced.”
We take a closer look at the science behind marathon running and how Caroline Wozniacki has been able to clock up the miles while still staying fresh for her matches.To read “Back in the Running” get your hands on a copy of our October 2014 issue (Volume 5 Issue 5) on sale now! Subscribe to the magazine today or download tennishead on iTunes.
Sarah Brown is principal of Good Food Works Nutritional Therapy. She has a particular interest in functional sports nutrition and digestive health, and provides personal consultations, coaching clients to reach their health goals by optimising their nutritional choices. She works in clinic at Pure Sports Medicine in south-west London.