The period of time leading into your next marathon brings a lot of distinct challenges separate to the race itself: tapering, traveling, eating, sleeping, etc. While important, these disparate elements don't matter as much as the fitness you bring to the starting line and the plan you have in place to reach the finish line.
Those two key factors aside, there's one more element of your marathon day that will make or break your ability to reach the finish line on time–your nutrition. Few things are worse than having excellent fitness, a great plan, the perfect day to race and then watching it all fall apart because your nutrition failed.
This article will break down how to plan out your race nutrition plan given what's available on the race course. The goal is to help you create a simple, repeatable solution that makes fueling so easy that you forget about it. Please note: This is only about nutrition consumed while running, not day-to-day food guidance.
Your Basic Fueling Needs
There are two main things you need to be concerned about when you run or race long: hydration and fuel. While most of us can run 60- or 90-minutes with only a little water, anything beyond that point without adequate calories will result in a very unpleasant–and likely sub-par–performance.
A marathoner can consume between 150 and 300 calories per hour. One gram of carbohydrates equals four calories, so the above range is between 38 grams and 75 grams. You should always start out low, adding fuel as you test your personal reaction to the calories. Remember it's always easier to add a bit more at the next aid station than it is to "get rid of" excess food in your stomach.
There really is no hard and fast guidance for this, especially with recent cases of hyponatremia (over-hydration). The basic protocol is to drink as frequently as you feel thirsty, and to help promote digestion of any fuel you are taking. On your longer runs this could mean taking a small drink every 10 to 15 minutes on a regular basis. On race day, this can be a simple as sipping fluids at every mile/aid station.