After many months of hard training, you won’t want to let your performance down on the big day by not getting your diet right in the final few days before.
Before the event:
On race day your main source of energy will be carbohydrates. Carbohydrate is stored both in the liver and muscle as glycogen. The main goal, prior to the marathon starting is to ensure that your glycogen stores contain enough for the event. In the 36-48 hours before the start it can be a good idea to consume 10-12g∙kg-1 per day from a variety of fruits, vegetables, breads, rice’s and pastas. This would equate to 700-840 grams for a 70kg athlete. To ensure fuel targets are met, small regular snacks may be beneficial as well as supplementing with carbohydrate beverages (sport drinks). Finally, choosing low fibre sources of carbohydrate may also be useful in reaching fuel targets and can also help reduce the likelihood of stomach distress during the race. A good option to help top-up the amount of carbohydrate in your diet would be Ultra Fine Scottish Oats as these can be added to shakes and smoothies easily.
On the big day, you should aim for a carbohydrate intake between 1-4g∙kg-1 in the 1-4 hours before the start. The amount that you decide to go for here and the time in which you eat should be personal in relation to what you feel comfortable running on. However, as a general rule you may find it beneficial to go for a meal that is low in protein, fat and fibre to minimise stomach distress. In addition, slow releasing carbohydrates may be a better choice for a more sustained source of energy over the course of the race. Adding dried fruit such as these Dried Whole Apricots to a bowl of porridge would be a fine choice.
You will also need to ensure you’re hydrated going into the race. Research demonstrates that even a small amount of dehydration (2% reduction in body mass) can decrease exercise performance. To ensure a hydrated status going into the race, you should aim for 6-8 ml of fluid per kilogram of body mass about 2 hours before the start. For example, an athlete who weighs 70kg would need to drink 420-560ml. An easy way of measuring hydration status is checking colour of urine, a clear to pale yellow indicates adequate hydration. A glass of water would do the trick here but Complete Hydration Drink™ can help with providing additional carbohydrates and electrolytes to your final prep if you need them.
Overall, ensuring you are fuelled and well hydrated before the start of the race should be your main focus. However, a supplement that may enhance performance further is caffeine. It is often taken for granted because it is such a common everyday product but many studies have examined its effectiveness. The majority of research has found a performance enhancing effect with a dosage range of 3-6 mg ∙ kg-1 taken 1 hour before exercise. You can buy caffeine in different forms: Caffeine powder and Caffeine tablets.
During the race:
The physical demands of the race will mean that you need to take on additional carbohydrate for energy and water to remain hydrated. Failure to achieve this will result in a drop in performance.
Carbohydrate can be provided via gels, drinks or bars – depending on which source you prefer. A good aim is to ingest between 20-70 grams of carbohydrate per hour. A gel will typically contain 25 grams, a drink 60-80 grams and a bar 25 grams. It would appear that a sports drink would be the best option because it provides the most carbohydrate but this is quite a large amount of fluid to ingest when running. Also, things are a little more complicated than simply ingesting large quantities of carbohydrate. It was thought that a maximum of 60 grams of carbohydrates per hour could improve performance and ingesting more would provide no further effect. For example, studies found that when larger amounts of carbohydrate are ingested (>100 grams) it did not result in more carbohydrate being used, instead the carbohydrate couldn’t escape the stomach due to the transporters that move the carbohydrate being overloaded and worked at full capacity. However, researchers found that combining different types of carbohydrates (such as glucose and fructose) resulted in a greater amount of carbohydrate being utilized during the race and the original 60 grams per hour could be increased to 90 grams per hour due to multiple carbohydrate transporters being used. The key message here is to rely on different types of carbohydrate, which gels typically provide, or consume carbohydrate during the race from bars, gels and drinks in order to ingest multiple forms of carbohydrate.
To maintain hydration status during the race and to prevent a 2% drop in body weight, you should aim to drink early on and often throughout the race. Ideally, you should drink to match your sweat rate but due to large variances in sweat rates between individuals and the impact different environments will play, it is difficult to generalize advice further than this.
After the race:
Marathon running is stressful! Muscle inflammation increases, the immune system is vulnerable to viruses, hydration status is lost and fuel tanks are depleted. To fully restore order, there are three main considerations during recovery; rehydrate, refuel and repair.
Even if you have managed to take on fluid before and during the race you will still most likely be dehydrated. To ensure complete rehydration it can be a good idea to weigh yourself before and after the race and replace any weight loss with 150% fluid. So a runner who loses 1kg in weight should drink 1500ml. Furthermore, after such a long event, you may also need to replace electrolytes, particularly sodium to allow fluid to be retained. Sodium may be taken on via Electrolyte powder or through adding salt to food or to existing meals.
The physical demands of the race will have taken its toll on your glycogen stores and you will be severely depleted. Research has shown that refuelling can happen at slightly higher rates in the first couple of hours post-exercise. This is popularly known as “the window of opportunity” for refuelling but unless you plan on exercising again within 24 hours, it’s not that important and you should focus on taking on an adequate amount of carbohydrate. A good place to start is 1g per kg body mass every hour until you get back into normal eating patterns.
Incorporating protein into your recovery meal, snack or drink will help muscle tissue repair following the stress of the race. In addition, immune function is depressed following such exhaustive exercise and ensuring an intake of protein and carbohydrate will help reduce the risk of illness following the race. In the immediate aftermath of the race, bacteria and viruses have their own “window of opportunity” and falling ill afterwards is common. An example of a source of good quality protein is Informed Whey®
Overall, you should try to optimise performance on the big day by ensuring your fuel tanks are well stocked before and during the race along with avoiding a level of dehydration that is detrimental to performance. Also, avoid any novel nutrition practices or foods you haven’t tried before as you will risk upsetting the gut. I hope you will find this advice helpful and I wish you the best of luck on the big day!
About the Author
Shaun Chapman is a Sport Nutrition consultant currently working with runners, cyclists powerlifters and people aiming to lose weight. With a background in football, Shaun has since competed in many running events, including 5km, 10km, OCR and half-marathon races. When he’s not marathon training, Shaun can be found in the gym working on his strength training.