How to Eat When Training for a Marathon -—Nutrition for Endurance Athletes

How to Eat When Training for a Marathon -—Nutrition for Endurance Athletes

So you have decided to do it—train and run in a upcoming marathon.  You figured with the right exercise regimen, time, and dedication; you will be able to cross this off your bucket list.  You spend hours researching how to manage your time and workout plan so that you can build up the stamina and strength needed for this adventure.  Now that you have a plan mapped out, you are almost ready to get started and train.  The one piece remaining is figuring out a solid diet plan that will allow you to have the proper fuel to allow you to make it to the finish line.  

Related: 8 Week Cross Training Program for Athletes (3 days/week)

Getting in shape to run a marathon, or compete in any vigorous sport for that matter, requires a combination of regular exercise and proper nutrition.  It is important to recognize that in order to reap the benefits of exercise, you need the right diet to ensure that you can properly fuel your body and build muscle.  As you get further and further along in training for the marathon you will find that what you eat can truly impact how long it takes you to complete the race. 

Carbohydrates First
When it comes to fueling your body, it is important to incorporate all three macronutrients, however one is most important.  When it comes to long distance running it is carbohydrates that serve as the main source of fuel.  It is most important to opt for complex carbohydrates over simple sugars, as they are digested more slowly, giving you longer lasting energy.  They will be used to serve as fuel, and will replenish and maintain glycogen stores.  Carbohydrates should provide about 60-70% of total calories while training for an endurance sport. The recommendation for a marathon runner is about 7 to 10 grams of carbohydrate per kilogram of body weight during the training period. These complex carbohydrates include foods like whole grain bread and pasta, cereal, brown rice, oatmeal, vegetables and low fat dairy foods. 

Protein and Fats 
The other two macronutrients, protein and fat, should both also be part of a balanced diet. It is important to consider the fact that protein is needed for muscle growth and repair, while fat has been shown to improve endurance.  In general a person, who is not training, needs about .8 grams of protein per kilogram of body weight.  When training the recommendation goes up to about 1.2 grams of protein per kilogram of body weight. Protein should make up about 15% of total calories per day.  Without enough protein while training, the body will break down muscle to fuel the body when running long distances.  With the right amount of protein in the diet, the body will be able to continue to build and maintain lean muscle mass.  Read more: How much protein do you really need? Consuming enough fat, in the form of healthy fats such as avocado and nuts, has been shown to increase endurance for marathon runners.  Endurance athletes should consume less than 30% of total calories from fat, with less than 1% from saturated fat.  By having fat in the diet, your muscles will burn more fat and less carbohydrate as you run.  The addition of fat will allow for you to run longer distances, as your muscle carbohydrate stores will not become depleted.  

Related: Meat is not the only source of protein; check out these plant protein sources for athletes and active people

Timing It Out
When deciding how often to eat and at what time, it is important to revolve this around the training run schedule.  It is recommended that one should eat a light snack or mini meal one to two hours prior to going on a training run.  This is important in order to fuel the body, while also giving your body a chance to digest the food prior to starting your run. Then be sure to plan for meals after your run to replace your body with the appropriate nutrients to replace energy and rebuild muscle.  It is also important to be sure you drink throughout the day to stay hydrated at all times.  

Sample Meal Plan for Runners
It is important to keep in mind that eating a well balanced diet will enhance your performance time when it comes to training for a marathon.  This means one should think about taking in nutrient dense meals and snacks, and keeping in mind the need to incorporate all three micronutrients.  It is recommended to start the day with a complex carbohydrate, along with a rich protein source.  And of course adding fruit will provide additional fiber and nutrients.  Some examples are: Greek yogurt with berries and whole grain cereal, oatmeal made topped with fruit, or a smoothie made with fruit or veggies, milk and bananas.   Lunch might include whole grain bread with turkey, avocado and greens or a salad with chicken, beans, and vegetables along with whole grain crackers.  Dinner can include a piece of grilled salmon, sautéed string beans and sweet potato or chicken, broccoli and brown rice.  The importance of your meal plan is to be sure to provide rich sources of complete proteins, complex carbohydrates and healthy fats. 

It is just as important that in addition to three balanced meals, you add in healthy snacks. Feeding your body on a regular basis allows for improved digestion and allows for your metabolism to remain intact.  Also, these snacks should be coordinated with the training schedule, as it is important to refuel your body after a workout.  These snacks or mini-meals should also be nutrient dense to meet the bodies needs, and maximize your ability to prepare for the marathon.  Snacks can include fruit and nuts, or peanut butter on crackers.

Hydration for Endurance Athletes
In addition to a carefully laid out meal plan, it is important to consider hydration.  A runner must keep in mind that as they sweat they will be losing body weight, and can compromise their fluid balance.  In fact losing as little as 2 percent of your body weight, through water loss, can have a significant impact on performance and recovery.  Water should remain the main source of fluids, with a daily intake of at least 6 to 8 glasses of water and more during the actual training.  While training, it is suggested that one add in about 8 ounces of water every 20 minutes that you are running.  For those running extra long distances, upward of an hour, might find the need to add in sports drinks for additional electrolytes.

Off to a Good Start
By taking the time to plan out a training schedule along with a balanced diet, you will be well on your way to finishing your first marathon.  Take the time to understand the various macronutrients your body needs to give it the proper fuel and allow for your muscles to repair.  As you get closer to the date of the marathon, learn about what to eat leading up the big day, what to eat the morning of the race and best post recovery foods.  Just a little planning and you will easily be able to go the distance and cross that finish line. 

Written by: M Mittler, MS Registered Dietitian