Can marathon runners have different carbohydrate requirements?

It is well-recognized that consuming carbohydrate during a marathon can increase running capacity and enhance performance by maintaining plasma glucose and high carbohydrate oxidation rates, sparing glycogen utilisation and by acting directly on the central nervous system. Current sports guidelines recommend an intake of up to 90g of carbohydrates per hour during exercise lasting over 2.5 hours. Your exact carbohydrate ingestion requirements will be influenced by several factors such as your training status, the intensity at which you complete the marathon, and importantly, how much carbohydrate can your stomach tolerate while running. Below, you can find two examples on how you can achieve different carbohydrate intakes while completing a marathon.  

1. This fuelling strategy will result in consuming ~60g of carbohydrate per hour, meeting the lower end of current sports nutrition guidelines for endurance sports lasting over 2.5h (recommended range: 60-90g CHO per hour). It includes the consumption of only single-source carbohydrates (i.e. maltodextrin), with the inclusion of fructose not providing any additional benefit at this hourly carbohydrate intake. Some nutritional training (i.e. consuming carbohydrates during training) is recommended to ensure you are used to consuming this amount of carbohydrate while running. This strategy also includes an hourly water intake of 500-700ml.

2. This fuelling strategy will result in consuming 80-85g of carbohydrate per hour, being recommended to runners who are used to ingesting higher carbohydrate intakes during running. It includes the consumption of multiple carbohydrate sources (maltodextrin : fructose) for increasing carbohydrate oxidation rates, which takes place if you are consuming more than 60-70g CHO per hour. Nutritional training is essential to ensure that your stomach can tolerate this carbohydrate intake during running. This strategy also includes an hourly water intake of 500-700ml.