Half Marathon Nutrition: What To Eat When Training For A Half Marathon

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Nutrition for half marathon training is one of the most important cornerstones of your training, yet often overlooked.

But what is the ideal half marathon nutrition plan? Is there an optimal half marathon training diet?

There’s a lot of information about how to fuel for a half marathon on race day, but what about your diet for half marathon training leading up to the race?

In this article, we will discuss half marathon nutrition, focusing primarily on the ideal half marathon training diet rather than race-day fueling.

We will cover: 

  • Why Is Half Marathon Nutrition Important?
  • Half Marathon Nutrition Plan: Here’s What to Eat When Training for a Half Marathon

Let’s jump in.

A person eating a granola bar.

Why Is Half Marathon Nutrition Important?

Nutrition is an often overlooked component of a runner’s training plan. We get so focused on the runs themselves, and perhaps even the auxiliary workouts like strength training and cross training, but we don’t tend to put much stock in nutrition for running aside from fueling for long runs and races.

While your diet is arguably less important when training for a 5k, half marathon nutrition is an essential constituent component of half marathon training.

In many ways, half marathon nutrition can make or break the difference between a healthy body and one that can’t fully recover after workouts.

If your diet is inadequate in one way or another, either not providing enough calories, carbohydrates, proteins, or other nutrients necessary to support training and recovery, or filled with processed and inflammatory foods that don’t provide your body with fuel that optimizes its performance, your training will suffer. 

Three people running in a field.

Inadequate caloric intake can increase your risk of injury, potentially making it impossible to even get to the starting line in a healthy enough place to run your race.

On the other hand, following a nutritionally-sound and supportive half marathon training diet plan can help you get the most out of your workouts by fueling your body and providing all of the necessary nutrients to facilitate recovery.

You will feel better on your runs, and your body will be able to make more favorable adaptations to all of the hard work you are putting in.

Although it can be tempting to think that if you are training for a half marathon, you are doing so much running that you should be able to eat whatever you want whenever you want, if you really want to run your best and feel your best, you need to take care of your body by putting in the “best fuel.”

This is not to say that you cannot enjoy treats; a half marathon nutrition plan does not, and frankly should not, only be foods that are deemed super healthy and nutrient-packed. You should be able to find a balance where you are mostly consuming nutritious foods and prioritizing your nutritional needs but still enjoying plenty of other treats.

A person eating a bowl of yogurt at the kitchen table.

In fact, one important thing to be mindful of is trying to maintain a healthy relationship with food as you become more serious with your training.

Some runners are prone to orthorexia, which is an eating disorder that revolves around the mindset that everything you put in your body has to be healthy and that there is no wiggle room for foods that you deem unhealthy. 

There can also be a tendency to feel like you need to “earn“ your calories, particularly in terms of “cheat meals.”

While it is all well and good and highly encouraged to follow a healthy half marathon nutrition plan, your diet shouldn’t take up a lot of mental space or cause anxiety. 

Focusing on eating well by having whole, unprocessed, nourishing foods most of the time should be your goal, with the awareness that it is also fine to have ice cream, cookies, or a celebratory meal that falls well outside of your normal half marathon training diet as long as you are meeting your nutritional needs and feeling good.

A good approach is the 80/20 or 90/10 diet. This essentially entails trying to make sure that 80% of your diet consists of nutritious foods and 20% of your diet is flexible to include any type of “junk food“ or less optimal fuel (or 90% and 10%, respectively).

A variety of snacks, including granola bars, rice cakes, fruit, and nuts.

Half Marathon Nutrition Plan: Here’s What to Eat When Training for a Half Marathon

A healthy half marathon nutrition plan should focus on unprocessed foods, with a balance of foods providing the three primary macronutrients—carbohydrates, protein, and fat—along with micronutrients.

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.

If you’re not sure how many calories you need to eat per day, consider using our TDEE and BMR calorie calculator that takes into account activity level. 

Carbohydrates

The bulk of the carbohydrates you should eat should be complex carbohydrates such as vegetables, whole grains, legumes, fruits, and tubers (potatoes, sweet potatoes, etc.)

Complex carbohydrates provide sustained energy because it takes longer to break down the long polysaccharides and fiber, and fiber supports digestion and satiety.

A cutting board filled with carbohydrates such as oats, wholewheat bread, pasta and flour.

When you consume a lot of simple carbohydrates or high-glycemic foods, your blood sugar increases rapidly after your meal or snack.

In order for your cells to actually take up glucose from the bloodstream and use it for energy or storage as glycogen, your pancreas must secrete insulin.

The hormone insulin signals your cells to absorb blood sugar, which ultimately decreases your blood sugar levels.

When blood sugar spikes quickly and rapidly after eating, the insulin surge can be equally dramatic, causing too much blood sugar to be pulled out of circulation.

This can result in a drop in blood sugar, termed reactive hypoglycemia, which can cause fatigue and rebound hunger. Basically, your body feels like you need more energy because blood sugar levels have dipped too low.

Except when you need quick-acting energy before and during workouts, consume well-balanced meals and snacks that contain low-glycemic, complex carbohydrates such as vegetables, legumes, and whole grains rather than starchy carbohydrates such as refined pasta, juice, and honey-glazed carrots.

This will help prevent high blood sugar levels and excessive insulin production.

A table of proteins including fish, poultry, eggs, legumes, and beef.

Protein

Consume lean protein such as poultry, fish, lean meat, eggs, soy, and low-fat dairy such as Greek yogurt and cottage cheese. 

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, so aim to eat about 20 grams of protein per meal or snack throughout the day.

Fat

We often hear about the importance of carbohydrates and protein during and after running, but fat is the body’s preferred fuel source for resting conditions and low-intensity training, such as Zone 2 workouts and long runs. Fats are also necessary for producing hormones, cell membranes and absorbing vitamins A, D, E, and K.

Good sources of dietary fat in a half marathon training diet include nuts and nut butters, seeds, coconut, avocado, fatty fish and fish oils, and healthy oils like olive oil and flaxseed oil.

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

Six different protein shakes.

Post-Run Fueling

Try to replace fluids, electrolytes, calories, carbohydrates, and proteins within 30 minutes after your run is over to start the recovery process. 

Most sports dieticians recommend a carbohydrate-to-protein macronutrient ratio of 3:1 to 4:1 in this post-run snack. It’s best to aim for 20 grams of protein, and 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 hours for the next 4–6 hours.

Examples of good post-run snacks include a protein-packed smoothie with Greek yogurt and fruit, nut butter on whole grain toast, a banana, oatmeal, eggs, etc.

There isn’t necessarily a specific macronutrient ratio to aim for on a half marathon nutrition plan, but sports dietitians often recommend 55% of your calories from carbohydrates, 25% from protein, and 20% from fat.

Your own needs may depend somewhat on the intensity of your training, your weight goals, and your food preferences. Working with a sports nutritionist or playing around with different macronutrient ratios can help you find a balance that works best for you.

If you are looking for specific meal and snack ideas, check out our helpful guides and recipes:

10 Awesome Protein Shake Recipes

The 26 Best Snacks For Runners

What To Eat After A Run: Post-Run Meal Ideas and Refueling Tips

A person meeting with their nutritionist to discuss half marathon nutrition.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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