Marathon Training Diet: What To Eat While Training For A Marathon

Running a marathon is arguably one of the most rewarding and empowering experiences, and can be more than just a bucket list item for many runners. Indeed, marathon training can be a lifestyle. When one marathon is done, the recovery period is often used to start planning the next one, several months out.

However, as rewarding as running a marathon is, marathon training is demanding in many ways. It takes a lot of time, effort, and energy, and is tough on your schedule, mind, and most of all, body. Therefore, your marathon training diet is a crucial component of your overall training plan in order to fuel your workouts and help you recover after each one.

A marathon training diet essentially needs to do two things: provide all the nutrients you need for overall health and support your marathon training and racing. But what should you be eating while you are training for a marathon? How does marathon training affect your nutrition needs? What is the ideal marathon training diet? Keep reading to find out.

In this guide, we’re going to look at:

• Components of a Healthy Marathon Training Diet

• Overall Structure of a Marathon Training Diet

• What to Eat On a Marathon Training Diet

• Determining Macronutrients for Marathon Runners

• Fueling for Running On a Marathon Training Diet

• Sample Healthy Marathon Training Diet Meal Plan

Ready? 

Let’s jump in!

Components of a Healthy Marathon Training Diet

In many ways, any good marathon training diet will look much like any other healthy diet. Marathon runners need carbohydrates, protein, fat, vitamins, minerals, and water, just as non-runners do. 

However, marathon training obviously requires a fairly significant energy expenditure, so a marathon training diet should be higher in calories than a standard diet. 

The number of calories you need depends on your metabolic rate, training volume, and weight goals. Your metabolic rate is dependent on factors such as your age, body size and composition, and overall activity level.

The number of calories you burn running depends on your size, speed, and the duration of your run.

Because carbohydrates are the primary fuel burned during higher-intensity physical activity, carbohydrate needs for marathoners are higher than for non-athletes and low-mileage runners. Protein needs can also be higher, as protein helps build and repair muscle tissue and enzymes.

For example, a standard diet might have 45% of the daily caloric intake coming from carbohydrates, 35% from fat, and 20% from protein, whereas a marathon runner might feel better with 60% of the daily caloric intake coming from carbohydrates, 20% from fat, and 20% from protein.

Overall Structure of a Marathon Training Diet

When it comes to diet, it seems the only universal generality that can be made is that there are no hard-and-fast best diets, best practices, or best meal plans. Eating seems highly personal.

Some people feel best eating three square meals a day and no snacks, while others find themselves feeling more energized and even-keeled with three smaller meals and three snacks. Others like intermittent fasting or other timing variations.

That said, in general, marathon runners often find it best to space their calories out throughout the day with meals and snacks at fairly consistent intervals. 

Depending on the time of day you do your runs and your nutrition and weight goals, aim for three meals and 2-4 snacks per day. Most marathon training diets encourage breakfast, lunch, and dinner, along with a snack between breakfast and lunch, one between lunch and dinner, and one before bed.

Runners who do their long run or hard workouts first thing in the morning should also consider a pre-run snack. After the morning run, you can have breakfast. Depending on the time of that meal, you might skip the snack before lunch or find you need that snack as well.

Essentially, there are no rules. Find what works best for you, but don’t be afraid to play around with different options and meal timing configurations.

What to Eat On a Marathon Training Diet

So what exactly does a marathon training diet look like in terms of foods? As mentioned, marathon runners need carbohydrates, protein, fat, micronutrients, and water.

Carbohydrates

Carbohydrates provide energy for high-intensity exercise, like most of your runs and workouts. 

There are two primary types of carbohydrates: simple and complex. Simple carbohydrates are simple sugars like fructose, glucose, and lactose and are digested and absorbed quickly.

Simple sugars are great right before and during a run to supply energy and top off glycogen stores without sitting around in your stomach while you try to work out. 

Good sources of simple carbohydrates for marathon runners include fresh and dried fruits, rice cakes, crackers, etc.

Complex carbohydrates have longer chains of sugar molecules called polysaccharides. They contain fiber and are often seen as searches. Complex carbohydrates provide sustained energy, and fiber improves digestion and increases satiety.

Good sources of complex carbohydrates for marathon runners include whole grains, vegetables, legumes, and tubers.

Protein

Protein provides 4 kcal of energy per gram and helps rebuild and repair cells and tissues. Because muscle is composed of protein, protein is crucial after training to aid recovery. 

For example, a review of 11 studies investigating the recovery benefits of ingesting protein along with carbohydrates after a bout of cycling versus ingesting carbohydrates alone found that adding protein to the post-exercise recovery fuel increased performance in the subsequent endurance ride by an average of 9% over consuming just carbohydrates alone. 

Therefore, a marathon training diet must have adequate protein needs.

Even though it’s important to refuel with protein after your run, studies have demonstrated that protein is absorbed and used most effectively when it’s spaced out throughout the day: every three hours in 20g doses rather than less frequently in 40g doses.

This is one reason why a marathon training diet that has meals and snacks rather than just meals is often more ideal for recovery and health.

Good sources of protein for marathon runners include lean meats, poultry, low-fat dairy, legumes, soy, seeds, nuts, and some vegetables.

Fats

Dietary fats contain 9 kcals per gram. Fat is the body’s preferred fuel source for resting conditions and low-intensity training, such as Zone 2 workouts and long runs. Fats also support hormone production, healthy cell membranes, and are necessary for the absorption of vitamins A, D, E, and K.

Good sources of dietary fat for marathon runners include nuts and nut butters, seeds, coconut, avocado, fatty fish and fish oils, and healthy oils like olive oil and flaxseed oil.

Hydration is key for any runner. Drink enough water throughout the day so that your urine is light yellow in color.

Determining Macronutrients for Marathon Runners

When considering the caloric content of food, each gram of fat contains 9 calories, while carbohydrates or protein each contain 4 calories per gram. 

This information can be used to help you determine how many grams of each macronutrient you want to eat per day. 

For example, let’s say your daily caloric needs based on your basal metabolic rate and general activity level is 1800 kcals. With the added average energy expenditure of your running, you are following a 2,400-calorie diet in order to maintain your weight and support your marathon training. 

For endurance performance, if you want to consume a recommended ratio of 55% of your calories from carbohydrates, 30% from protein, and 15% from fat, you can determine the grams of each macronutrient as follows:

Carbohydrates: 2400 x 0.55 = 1320 calories

1320 calories / 4 calories per gram = 330 grams

Protein: 2400 x 0.3 = 800 calories

800 calories / 4 calories per gram = 200 grams 

Fat: 2400 x 0.15 = 400 calories

400 calories/ 9 calories per gram = 44 grams

You’ll certainly find variations in the recommended macronutrient ratios for marathon runners and other endurance athletes. You can experiment with different ratios to find what works best for your body and dietary preferences.

Fueling for Running On a Marathon Training Diet

Once you have a healthy diet that supports your overall nutrition needs and health, you’ll want to look at fueling your runs.

In general, you shouldn’t have to worry about specific fueling for any run that’s an hour or less. The one caveat is that if you’re running first thing in the morning, you might want a small snack of simple carbohydrates before you head out to top off blood glucose after the nighttime fast. 

Examples include half a banana, a few dates or dried apricots, or a few bites of oatmeal or toast.

In contrast, before long runs and your marathon itself, fueling properly is paramount. Most runners should strive to get 100g of carbohydrate in the pre-race breakfast, and then aim to consume 30-60 grams of carbohydrates per hour during the race. 

Again, simple carbohydrates are best, as foods with fiber, fat, and too much protein will take longer to digest and can cause GI upset while running.

After a workout, runners should aim to replenish fluids, electrolytes, calories, carbohydrates, and proteins within 30 minutes after cessation of activity. Most sports dietitians recommend a carbohydrate to protein macronutrient ratio of 3:1 or 4:1 in this post-run snack.

The standard recommendation for carbohydrate refueling after exercise is to consume 0.6–1.0 g/kg carbohydrate within 30 min and again every 2 h for the next 4–6 h.

Examples of good post-run snacks include a smoothie made with Greek yogurt, banana, berries, spinach, and almond milk; yogurt, low-sugar granola, and fruit; multigrain toast with nut butter and sliced apple; or oatmeal and eggs.

Sample Healthy Marathon Training Diet Meal Plan

Curious what a day following a healthy marathon training diet might look like? Below, we share three different days following a healthy marathon training diet:

Day 1: Morning Long Run

• Pre-Run Snack: Whole wheat toast or English muffin with peanut butter and sliced banana 

• Long Run: Consume 60 to 90 grams of carbohydrate per hour with some fat and protein throughout such as trail mix with dried fruit, nuts, and dark chocolate or whole grain tortilla with almond butter and honey.

• Post-Run Recovery Snack: Protein smoothie with banana, spinach, blueberries, pineapple, hemp seeds, Greek yogurt (or coconut yogurt if you are vegan), and protein powder.

• Late Lunch: Hummus with whole-grain crackers, carrots, pepper strips, celery, and cucumbers; red grapes.

• Dinner: Fajitas with chicken or tofu, black beans, brown rice, peppers, lettuce, onions, tomatoes, corn, salsa, and vegan or regular cheese. Spinach salad on the side. 

• Snack: Cottage cheese with sliced almonds, strawberries, and cocoa nibs.

Day 2: Rest Day (No Running)

• Breakfast: Omelet with eggs, cheese, peppers, onions, spinach, and mushrooms.
  
• Snack: Blueberries and pistachios.
  
• Lunch: Large salad with spinach, arugula, cucumbers, tomatoes, sprouts, chickpeas, sunflower seeds, snap peas, broccoli florets, and craisins. 

• Snack: Tuna fish or hummus with carrots, celery, pepper strips, and cucumbers.

• Dinner: Roasted turkey breast or grilled tofu over quinoa and lemony wilted greens. Broccoli on the side.

• Snack: Apple and string cheese.

Day 3: Evening Interval Workout 

• Breakfast: Overnight oats made with almond milk, chia seeds, flax seeds, hemp protein powder, blueberries, cinnamon, and unsweetened coconut flakes.

• Snack: Peach or plum.

• Lunch: Brown rice with grilled chicken or tempeh, roasted Brussels sprouts, kale, walnuts, and sesame seeds.

• Pre-Run Snack: Rice cakes with peanut butter or natural energy bar.

• Hard 60-90 Minute Interval Workout: Water or sports beverage. Dinner to follow or have a banana with nut butter after the workout.

• Dinner: Roasted salmon or tofu steaks with baked sweet potato, Greek salad, and asparagus. 

• Snack: Greek yogurt with low-sugar granola and raspberries.

For more information, and a free download of our very own marathon training meal plan, click here!