Marathon Training Diet Plan

Training for a marathon takes dedication, time and proper fuel in the form of a solid diet plan. While you're training, keep an eye both on the snacks you eat to power a long training run and on the nutritious meals you eat throughout the rest of the day -- both can make a difference between eventually crossing the 26.2-mile finish line or hitting a wall in the middle of training.

A marathon runner must eat a proper diet to fuel her training. (Image: m-imagephotography/iStock/Getty Images)

Focus on Carbohydrates

Although all three macronutrients are important for distance runners, carbohydrates are the cornerstone because they're your body's preferred source of fuel. According to registered dietitian Janice H. Dada in "Today's Dietitian," a marathon runner needs between 7 to 10 grams of carbs per kilogram of body weight during the training period. Aim to include plenty of complex carbohydrates on your diet plan, including whole-grain bread and pasta, brown rice and legumes. Running coach Hal Higdon recommends limiting simple carbs, such as honey, sugar and jam, to 10 percent of your calories.

Fueling for Runs

Much of your diet plan will revolve around your training runs. ITCA-certified triathlon coach Michelle Portalatin told "Shape" magazine that you should eat a light, energizing snack or small meal one to two hours before you go for a training run. One option could be breakfast cereal with fruit and 1 percent milk, suggests Dada. If solid food is too much for your stomach, sports nutritionist Sotiria Everett recommends a fruit smoothie made with milk and a banana. Avoid foods that are high in fat, fried or have a rich sauce, as well as high-fiber foods, all of which can cause stomach problems during your run.

Potential Meal Plan

For the remainder of your diet plan throughout the day, aim to eat well-balanced, nutrient-rich meals. Start the day with oatmeal, a complex carbohydrate, topped with cherries, which are rich in antioxidants, and a glass of milk, or a smoothie made with fruits, green vegetables such as spinach or kale and a natural protein source such as Greek yogurt. Fuel up at lunch with a whole-wheat pasta salad mixed with plenty of vegetables and a source of protein, such as chickpeas or canned tuna. For supper, plan dinners around lean proteins such as chicken or salmon; the omega-3 fatty acids in the latter improve exercise performance by increasing heart stroke volume, according to Competitor. Pair it with a side dish of black beans and a green salad or roasted vegetables. If you're a vegetarian, try soy products for your protein, such as tofu, as it promotes muscle recovery.

Importance of Fluids

Proper hydration is a vital part of a marathon runner's diet plan; losing as little as 2 percent of your body weight through water loss can affect your running performance and recovery, says registered dietitian Tara Gidus. For daily drinking, stick with water, carrying a bottle with you at all times. During your training runs that are longer than 60 minutes, add sports drinks that replace carbs and electrolytes lost during training. Aim to drink 4 to 8 ounces every 15 to 20 minutes.