By Christopher R. Mohr, PhD, RD
It's race day. Marathon day. 26.2 miles. You've been training for the last several months, preparing for everything within your control. One of the biggest factors that will determine how you finish is sports nutrition and how you fuel your body. This single fact alone can be the difference between barely finishing a race and finishing strong.
So what should marathoners eat? What should they drink?
First things first, it's important to emphasize that nutrition for marathon training isn't limited to just a few days here and there. It's the time during training, the days leading up to the race AND pre, during and post that is important to finish a marathon feeling great.
Carbohydrates and Protein Are Important
As a general rule of thumb, the diet for someone who is training for a marathon should be carbohydrate based to provide adequate glycogen to the muscles for energy during training and the event itself. This is usually not a big issue for endurance athletes. Carbohydrates are usually the "basis" of the diet.
On the flip side, protein often can be an issue since the focus is normally so heavy on carbs. But while carbohydrates are important, it's just as important that they don't replace protein. Carbohydrates provide necessary energy. Protein provides the tools—amino acids—to build and repair damaged muscle from the miles and miles of training done each and every week.
Hydration can be argued to be more important than carbohydrates, protein or fat. Dehydration is the single largest contributor to fatigue when training or racing. Sweating helps regulate the temperature of your body. This is important. However, the loss of fluids and electrolytes—primarily sodium—also means these need to be replaced to prevent becoming dehydrated and, subsequently, hurting performance.
Sports dietitian Pam Nisevich Bedes, co-author of the Runner's World Big Book of Marathon and Half-Marathon Training, suggests, "In the days before race day, runners should be certain to focus on their hydration in order to ensure they arrive at the starting line well-hydrated. Drinking until urine runs a light straw color is optimal."
On race day, runners need only focus on "topping off their tank. I would recommend they do so with a sports drink as it offers not only water but also electrolytes and carbs which will come in handy once the race begins," says Nisevich Bede. "Runners should stop drinking approximately 30 minutes before the race begins in order to give them time to use the facilities."
One reason hydration is important is because it takes just a 2% weight loss to hurt performance. For the average 164 lb. woman, that's just over 3 lbs.; something that can occur when exercising in the heat or humidity
On that note, sports dietitian Christine Gerbstadt emphasizes “...be sure to check which sport beverage will be available on the marathon course. You may want to carry your own flavor or brand or have someone offer you your brand on the route. Don't find out at mile 13 that you hate the sport beverage the race offers."
Replenish During the Race
Outside of hydrating during the race, it's important to consider your fuels to replenish your hard working muscles. Gerbstadt offers this suggestion: if you are running under three hours you can just take water or a sport beverage. Another option is to take a carbohydrate gel, or "sport beans" at the half and 20 mile points, and water as needed.
However, if you are running a three- to five-hour marathon you may need more fuel, consider your carbs (carbohydrate gel, sport beans) earlier, like at the 10k mark and every 10k thereafter.
Recover with the Right Fuel After the Race
"Celebrate" with the right recovery fuels. "Many runners finish a race dehydrated and for optimal recovery, it's important to start rehydrating immediately," says Nisevich Bede. After crossing the finish line, grab a bottle of water or sports drink. In the hours following a marathon, runners should continue to hydrate and drink 24 oz. of liquid for each pound lost during the race. Be careful not to over hydrate with water alone; runners will want to focus on replacing vital electrolytes that they lost while running. This comes most easily from a sports drink.
It's also important to consider protein to help your muscles recover. This can be as simple as adding 10-20 grams of whey protein to your favorite sports drink, or if you want a solid meal, including some protein rich foods with whole grains. Because it's common for runners not to be hungry post exercise, opt for low-fat chocolate milk or a sports drink with whey protein.
One other important note — while there are many tips, tools and suggestions throughout this article, it's important to remember to never try anything new on race day. Always do the experimenting during a training run, so you know how your body will handle whatever fuel you are using and can best be prepared to finish the race strong.
Also, check out these books for the latest information on nutrition for running and other sports.
Reviewed April 2013
Christopher R. Mohr, PhD, RD is co-owner of Mohr Results, Inc., a nutrition consulting company based in Louisville, Ky. He is an internationally recognized expert in nutrition and is a consulting sports dietitian for the Cincinnati Bengals.