5 Top Marathon Training Nutrition Tips to Run a Faster Marathon

Olivia Minicucci, MS, RDN

man and woman running in dessert marathon training nutrition

Check out these must-know marathon training nutrition tips to improve your mile time and make your running journey more enjoyable. 


Training for a marathon is far from a walk in the park. No, really, it’s 26.2 grueling miles that challenge the body and the mind in unexpected ways. But whether you are an experienced racer or an ambitious newbie, fueling the body adequately can get you across the finish line at a record pace. Here are 5 key marathon training nutrition tips to remember.

  1. Fuel properly for different lengths of runs

  2. Train your gut

  3. Hydrate before, during, and after

  4. Get friendly with electrolytes

  5. Fuel for recovery

And even if you aren’t in the midst of marathon training, these strategies can help with your workouts, sports, and even the “marathon” of each day at work and at home. Now let's take a close look at each one.


1. Fuel Properly for Different Lengths of runs


Marathon training is more than simply channeling your inner Forest Gump. It includes a combination of short, medium, and long runs along with speed work, resistance training, and active stretching. In other words, running a marathon is a part-time job—each day requiring a specific fueling routine.


But, being well versed in all types of exercise can help improve overall performance while minimizing the risk of injury. So, check out this easy guide to go the extra mile, no matter what the distance!


Nutrition for Short Runs (<60 minutes)


Just get out there and have some fun! While no additional carbohydrates are needed while exercising, short runs can get used as a stepping stone to training the gut to tolerate pre-exercise fuel. 


Nutrition for Medium Runs (60-90 minutes)


This distance eventually becomes every athlete’s comfort zone. Make the most out of your workout by aiming to consume approximately 30 to 60 grams of carbohydrates per hour. Before the run, avoid foods overly high in fat or fiber since they can slow digestion and may induce stomach pains while running. 


Nutrition for Long Runs (90+ minutes)

Without question, this is the hardest (and sometimes most dreaded) day of the week. However, it’s the ideal time to experiment with race-day fueling tactics. To power through your milage, pump up the carbohydrate intake to 60 to 90 grams an hour.


However, be sure to ramp up your fuel slowly to avoid unwanted gastrointestinal distress. Don’t forget to include various carbohydrate sources such as gels, chews, drinks, and bars to improve overall absorption and tolerance. After all, there isn’t anything worse for your split time than an unhappy stomach!  


Speed Work Marathon Training Sessions


These workouts often get neglected by runners. After all, we aren’t sprinters! While they may be outside a marathoner’s comfort zone, they are essential for improving your mile time. However, it can be challenging to fuel the body adequately with your body moving at lightning speed. So, stick to sports drinks to help reach your nutrient and electrolyte needs. 

2. Train Your Gut

Running wreaks havoc on your gut. It’s common to experience nausea, cramps, gas, or diarrhea after pushing your body to the limit. It’s true what they say, “never trust a fart after mile 20.” But, for some, the discomfort may seemingly begin while still spitting distance from the house, usually resulting from an untrained gut. However, while running in a fasted state may feel more comfortable, it’s a missed opportunity to get your stomach ready for race day. After all, glycogen stores can only power your legs so far.

Keep the body running to your next mile marker rather than the bathroom by training your stomach to tolerate fuel before and during exercise. With a little practice, you will be able to trust your gut to get through your race without pain or unwanted pit stops. To get started:

  • Have a few bites of easy-to-digest, soft-consistency foods such as oatmeal, yogurt, overnight oats, or banana before hitting the streets or treadmill.

  • Remember, one bite is better than none.

  • Slowly increase the quantity of food to get your gut accustomed to multitasking digestion and diverting blood to working muscles. 

  • The same principle can get applied to intra-workout fuel. Start with energy drinks or gels and eventually work your way towards more substantial fuel sources. 

While it may be a slow (and possibly uncomfortable) process, your body will appreciate it come race day. 

3. Hydrate Before, During, and After Training

Lots of runners are early birds—clocking miles before work, school, or family obligations. But, after a night-long fast, many athletes hit the ground running while already in a partially dehydrated state. Although they may drink on the go, playing a game of “catch up” can negatively impact exercise performance.


So, give yourself ample time to drink water before your sweat sesh to help maintain your splits. Just remember that when it comes to hydration, slow and steady wins the race. So, to maximize fluid absorption, be sure to sip rather than chug. Then, continue these habits during your run, aiming to consume approximately 20 oz of fluid per hour of exercise. To put into practical measurements, each big gulp of water is around 2 oz. So, all it takes is about 10 sips an hour to reap the benefits of well-hydrated performance. However, these needs can significantly increase with environmental conditions such as heat or humidity. 

Once you get home and kick off your shoes, the recovery process begins, starting with rehydration. Ideally, weigh yourself both before and after your run to help decipher your fluid loss during exercise.


To ensure adequate rehydration, consume 16 oz of fluid per pound lost during your run. Then, maintain a slow yet steady fluid consumption throughout the rest of the day to reach your needs. To help get your daily sips, keep your water in plain sight or grab a trendy bottle to spark your motivation. 

4. Get Friendly with Electrolytes

Part of “hitting the wall” may have to do with an electrolyte imbalance. It’s also a common reason for ramping split times, ultimately putting your desired personal record into question. But, while you may stay on top of your fluid intake, water alone cannot get your legs to the finish line.


Through sweat, electrolytes such as sodium, potassium, magnesium, and chloride get lost, ultimately impacting athletic performance. Loss of electrolyte levels may increase heart rate, muscle cramping, fatigue, and other factors that make this seemingly endless run feel that much more challenging. So, incorporate electrolytes to preserve your pace for added miles while also helping to mitigate heat-induced performance detriments.


It can also help prevent post-run headaches and improve overall rehydration, ultimately contributing to better recovery. To help reach your needs, experiment with an electrolyte-containing beverage or tablet. Personally, I enjoy the chewable salt tablets since they are easy to consume during a run. Don’t worry; they taste sweet! It’s a small yet crucial component to better performance! 

5. Fuel for Recovery 


Fueling is not just about today’s run but tomorrow’s as well. Countless days of pounding pavement causes wear and tear on muscles, bones, tendons, and ligaments, ultimately increasing the likelihood of injury. So, it’s essential to give your body the building blocks it needs to repair from the daily strain. After all, when it comes to training for a marathon, half the battle is not getting injured.


Plus, having a well-fueled body can help prevent your legs from feeling like bricks, contributing to a better running pace. So, be sure to pump up the calories, protein, carbohydrates, and other nutrients that can help keep your body in tip-top condition.


Don’t forget to include between 1 to 3 grams of leucine to help stimulate muscle protein synthesis. Leucine-rich foods such as tempeh, legumes, tofu, and Greek yogurt can help rebuild muscle tissue and minimize injury risk. While a food-first approach is always preferred, talk to a registered dietitian about the appropriateness of recovery supplements or nutrients. 


Olivia Minicucci, MS, RDN is a Columbia University graduate, where she completed both her dietetic internship and earned a master’s in Nutrition and Exercise. She is passionate about writing and editing and is active on Instagram. Olivia is a competitive equestrian show jumper and also enjoys weightlifting, running marathons, and skiing. Throughout her academics, Olivia has published several sports nutrition articles in scientific journals, such as Nutrients and Elsevier. After being in the competitive equestrian community for over a decade, as well as a marathon runner, Olivia has specialized in the nutritional and physiological issues among equestrian athletes and runners. Visit her at www.minifitnessdiet.com.