How Much Should I Eat When Marathon Training?

Training properly for a marathon means that you’re going to be running a lot of miles. Most likely more than you ever have. It’s possible you’re replacing different types of calorie-burning workouts with all of your extra running mileage, but for many runners, marathon training will result in more calories burned than typical. Which means you’ll be hungrier, right? But just how much should you really be eating during marathon training to maximize your running without going overboard?

Every runner is different when it comes to how much they should eat in marathon training because of height and weight differences as well as personal metabolic rate. On average, a moderately active person needs around 2,000 calories per day to maintain weight. And for every mile run, you burn around 100 calories. That means that if your marathon training has you running 50 miles per week, in a perfect world you’ll have an extra 700+ calories to eat per day for a total of 2,700 daily calories.

But is it really that simple? In this article, I’ll discuss how much you should be eating (and if you really need to replenish every calorie “burned”), when you should be eating more or less throughout the week depending on your training and what the best foods are to eat to feel good and run your best.

How Much You Should Eat in Marathon Training

Those extra 5,000 calories you’re allowed sounds like a lot, right? That equates to an extra 700+ calories each day.

In actuality, that doesn’t necessarily mean you should be eating 700 more calories per day and it certainly doesn’t mean you can just eat whatever you want. Because on top of not wanting to gain weight while you train for a marathon (it’s easier than you might think and you can read more about that here), you also want to make sure you feel good and have the energy you need to run all those miles. In other words, that 700-calorie hamburger from McDonald’s shouldn’t be making its way into your daily menu just because you “can.”

On the flipside, getting in all those extra calories might sound daunting. In fact, a study on 25 competitive athletes completed by a sports dietitian published on Active found that they weren’t eating enough…surprisingly, there was an average of a 700-calorie daily deficit. I would venture to guess that most runners continue to eat the way they have in the past because it’s in their embedded routine.

You don’t want to overfeed yourself but you don’t want to be underfed…so what should you do?

When trying to figure out how much to eat during marathon training, it’s best to pay attention to your hunger cues. I know it sounds simple, but it really doesn’t need to be complicated. And if you’re feeling a lack of energy when you add miles, double-check that what you’re eating are whole foods that fuel the body instead of a bunch of junk. It may just be you need to add a couple more hundred calories from foods that help beat fatigue such as those listed in Medical New Today: eggs, bananas, oats and spinach to name a few.

I know some people like knowing the numbers, so let’s talk a bit about what IS proper calorie intake.

How many calories should I eat a day training for a marathon?

The fact is that as you run more and more, you’ll actually use energy more efficiently and ultimately burn less calories than you think you should be…perhaps you’re not burning 100 calories for every mile you run afterall.

The best amount of calories to take in is the amount that’s going to take care of your body to perform its best while putting it under a lot of stress. We’re focusing on weight maintenance and having energy (not weight loss).

To determine how many calories you should be eating per day while marathon training you’ll want to first consider:

  • how many miles you’re running,
  • whether you’re a man or a woman,
  • and how much you weigh.

To start, you want to look at how many calories you need to maintain energy balance as a sedentary human. This chart shows several examples, but for women, that’s 1,800-2,000 calories per day and for men it’s between 2,200 and 2,400 typically. Then you’ll want to look at your daily mileage. If you burn roughly 100 calories per mile and you go for a 6-mile run, then you just burned 600 calories.

A rough estimate would make you assume you could eat 2,000 calories per day plus 600 more and still maintain your weight.

But utilizing something like the METs calculator can help you get a bit more specific. A MET is a “metabolic equivalent of task” and estimates how many calories are burned during common physical activities and takes your weight into account. I like this one because it even has you put in the pace you’re running at which makes a difference. Though not perfect, this will give you a good idea of how many calories you are burning on top of what you would burn typically without exercise.

It’s also important to remember that you may not actually need all 600 of those calories you supposedly burned to replenish and feel your best. This is because your body gets really efficient at using energy and ultimately uses fewer calories than what a calorie tracker would tell you. So though you can use this as a guideline, more importantly, you want to pay attention to your hunger cues. Don’t eat extra just because you think you can.

Will I lose weight during marathon training?

Some people may want to combine marathon training with their weight loss goals. But, marathon training isn’t the best exercise for weight loss.

Coach Claire shared on the Run to the Top podcast that calories burned begins to plateau as you increase activity. This means that even though you’re increasing your activity, you’re likely burning near the same number of calories as you were when you were moderately active. Say whaa??? Now, if you’re in a couch to marathon situation, that’s different, but most people who are training for a marathon were already running before that. You’re not just going to immediately start shedding pounds because you’re upping the mileage.

Let’s go back to the study about the runners who were short 700 calories on the daily. You’d expect them to be losing weight week-by-week, right? But they didn’t. The article goes on to say, “The human body has an ability to adapt to a lower level of energy intake, allowing for preservation of weight despite a calorie shortage. Unfortunately, this means the body is less efficient at using the calories and nutrients consumed during training.”

So if you’re wondering if you’ll lose weight during marathon training, don’t count on it. It’s not uncommon to lose a few pounds, but it likely won’t be significant for most people. The best thing you can do is focus on eating in a balanced manner with a focus on most of your diet coming from the most healthy foods, which we’ll talk about below. And though you don’t need to be counting calories, it is good to have an idea of how much your body needs to be your best running self.

And if you are set on losing weight while training for a marathon, working with a nutritionist or at least seeking their advice initially is a good idea.

What should I eat while training for a marathon?

First and foremost, the best approach to nutrition when training for a marathon is to eat intuitively and pay attention to your hunger cues. I know that’s harder for some than others, but if you can get a handle on giving in to your body’s cravings with healthy foods that fill that need while eating when you feel hungry (instead of eating a huge delicious cinnamon roll because you “earned it”) you’ll have the energy you need to train while feeling great and maintaining your weight.

You want to eat a balanced diet of macronutrients: carbohydrates, protein and fat. These are all good things your body needs! Additionally, your body thrives off of a mix of vitamins and minerals that come from vegetables, fruit, grains and lean meat.

Whole foods will be your best friend during marathon training and getting plenty of them to keep your energy up is the way to go.

Here are some good rules of thumb to follow:

  • Eat easy-to-digest carbs pre-run to fuel yourself
  • Aim to get a blend of healthy fats (such as avocado, olive oil and nuts), protein and carbohydrates post-run to replenish burned calories and start the recovery process as well as electrolytes. Interestingly enough, chocolate milk is a very popular way to get all of this at once which I wrote about here. (Just keep it to an after long run treat instead of something you have all the time.)
  • Carbs are your friend as an endurance runner! Aim to have around half of your diet come from carbs, while balancing the rest with fat and protein
  • Drink plenty of water
  • Eat when you’re hungry
  • Focus on getting 3 healthy, balanced meals in per day with at least 2 healthy snacks

If you’re looking for some recipe ideas, cookbooks written by runners can be a great place to start.

Keep in mind that if you are vegetarian or vegan, you’ll need to be extra cognizant that you’re getting all of the nutrients you need. Be sure to do your research in this area or consider reaching to a nutritionist who works with vegetarian and vegan athletes.

In terms of determining what to eat before a run, it’s important to eat easy-to-digest foods. If it’s an easy run, you may consider fasted running which I cover here. Otherwise, my go-to is usually an RXbar or similar, or piece of white toast and peanut butter with half a banana.

Considering what to eat before a LONG RUN is extra important. This includes planning out your meal the night before, as well. To ensure you have a great long run that doesn’t leave hunting up a bathroom or lacking energy, be sure to ready “What to Eat Before a Morning Long Run.”

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Watch the video and find out the best and worst foods to eat before your long run.

And of course, you need to take in nutrition during your longer runs as well in order to keep your body stocked with glycogen until your run is over. For idea and timing be sure to read, “Long Run Nutrition: Foods to Eat During Your Marathon.”

What should I not eat when training for a marathon?

It’s never fun to completely restrict something from your diet that you enjoy eating and there’s no reason you need to do that during marathon training either. With that said, you do want to be cognizant of the foods that you are eating and aim to eat as well-balanced of a diet as possible based on the recommendations above.

It’s ok to treat yourself once in awhile, but keep less healthy foods to a minimum. This includes those high in added sugar or sodium, fried food, and processed meats and cheeses. Alcohol and sugary drinks (even juice) are included in that list. Doing so will help you to feel your best!

You also want to take care what you eat before you go running. Even some very healthy foods can make you feel like junk on a run. Stay away from anything that’s difficult to digest – such as most whole grains (oatmeal is generally ok), high fiber fruits and vegetables, beans, spicy foods and fatty meats and cheeses.

Marathon Training Nutrition Isn’t Rocket Science

It’s a good idea to know what you should be eating during marathon training and how much in order to feel great and run your best. It’s also important to keep your eating in check so as not to go off the rails thinking you can eat whatever you want just because you think you earned it. That mindset will only serve to backfire.

In reality, the nutrition recommended for marathon runners isn’t that different than it would be for everyone. You’ll just need more of those nutritious foods to stay strong and energized and ready for the miles. Ensuring you eat enough during your long runs and being sure to eat after a run are key during marathon training, too.

Though weight loss can be a nice side benefit and you may lose a few pounds, focus on the fact that you’re becoming incredibly fit while striving to reach your goal of finishing a marathon.

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Marathon Running Tips & Tricks

New videos posted every Sunday. Watch them while recovering from your weekend long run!

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