The Expert Guide on What to Eat Before, During & After a Marathon

In this article:

Why You Need to Eat and Drink During a Marathon

During a marathon, your body works hard to supply your muscles with the energy and oxygen they need to keep pumping. Like a car needs gasoline, your body needs plenty of carbs and fluids to keep you running smoothly. When you consume carbohydrates, your body breaks them down into glucose. It can use the glucose immediately or store it as glycogen, mainly in the liver and skeletal muscles. 

During exercise, your body starts using glucose (in the bloodstream and from glycogen stores) and fatty acids (from fat stores) to produce the ATP required for muscle contraction. However, prolonged exercise like long-distance running can deplete the body's glycogen stores. Also, higher intensity activities require a certain amount of glycogen as a fuel source. Glucose and glycogen are the primary sources of fuel at exercise intensities greater than 60% of maximal oxygen consumption (VO2max). 

What Happens When You Hit the Wall?

So why do marathoners hit the "wall" and what exactly is it? Hitting the wall or "bonking" occurs when your body runs out of glycogen; it's like your car running out of gas. This typically happens around mile 20.

When your glycogen tank is empty, your muscles cannot continue to fire. Your body's reaction is both physical and mental; your brain signals the body to stop, and you may experience mental fog. Runners are overcome by extreme fatigue and legs that feel like lead, which forces the body to come to a screeching halt. When you properly fuel your body with carbohydrates throughout your run, however, you'll keep gas in your tank and avoid the dreaded wall.

- Stephanie C. Hodges, MS Nutrition and Exercise Science

How Much Do You Need to Eat and Drink?

When it comes to fuel, hydration is critical during physical activity, particularly during endurance events and on hot days. The American College of Sports Medicine position statement, based on a comprehensive review of the scientific literature, outlines the following guidelines for exercise and fluid replacements:

1. Individuals should consume a nutritionally balanced diet and drink adequate fluids within the 24 hour period before the event.

2. Drink 17oz (about 500 ml) of fluid within 2 hours before the event.

3. Drink fluids at regular intervals throughout the event to replace all water lost by sweating or the maximal amount tolerated.

4. For exercise lasting longer than one hour, consume 30-60 grams of carbohydrate per hour. Consuming 20-40 oz (600-1200 ml) of a sports drink containing 4%-8% carbohydrates can provide the recommended intake.

Options For Marathon Running Fuel

Alternating water and carbohydrate-electrolyte beverages (like a sports drink) is critical during a marathon. You can also rotate other carbohydrate sources into the mix. For example:

• Energy Gels: Gels are fast-digesting, easy to use fueling sources during exercise. A typical serving of gel contains around 25 grams of carbs.

• Energy Chews or Sport Beans: These chewy energy sources are ideal during exercise; they're fast-digesting and easy to eat on the go.

• Energy Bars: Energy bars pack more carbs and bulk, and come in many flavors, shapes, and sizes. 

• Food Options: There are many personal preferences here, but some common options are bananas, bagels, granola bars, fig newtons, peanut butter crackers, and even peanut butter and jelly sandwiches.

All gels, chews, bars, and food should be chased with water (not sports drinks). This ensures your body gets the proper amount of fluid and can properly digest the carbs. Try to alternate carbohydrate+water with sports drinks when refueling along your run.

Avoid Digestive Discomfort While Running

Not everyone can tolerate solid food while running. And remember: do not try something brand-new on the starting line of your marathon race! It's absolutely essential to test your body's reaction to gels, bars, and food options. Try small amounts on shorter runs and gradually build up to see what your digestive system tolerates best.

Use the long runs on your training plan to chart out every aspect of your race. This includes what to wear and how early to wake up. And of course, what and when to eat and drink. Although it's vital to have fuel in your system, you don't want to eat and drink too much. Some problems from overeating and overhydration include:

• Water sloshing in your stomach

• Feeling heavy with too much food in the stomach

• Acid reflux or regurgitation

• Cramping

• Having to go to the bathroom multiple times during your run

• In severe cases, hyponatremia (although rare, this is a disruption in sodium balance from overhydration.)

Fueling Your Marathon

So let's talk about exactly how to fuel every mile of your race. Your energy stores are affected by what you eat in the days leading up to your marathon. 
Also, remember that running causes wear and tear on your body. A good

supplement routine throughout your training program and after your race will help your body repair and stay injury-free. Three top supplements to consider are:

• Collagen: helps maintain healthy joints and connective tissues, preserves muscle mass, and provides your body with high-quality protein.

• Liposomal Vitamin C: a powerful antioxidant to help you produce collagen, decrease fatigue, and strengthen your immune system.

• Liposomal Glutathione: the body's "master antioxidant" helps fight free radicals, detox your body, and support your immune system.

What to Eat the Week Before Your Marathon

Try to stick with your regular healthy eating plan during the week leading up to your race. Eat familiar foods that your body tolerates well to avoid any digestive upset. Avoid heavy intake of alcohol, high-fat, or greasy foods that could cause digestive discomfort or sluggishness.
Eat a healthy mix of carbohydrates, proteins, and fat. While recommendations vary, a good standard is:

• 55-65% of calories from carbohydrate

• 20-25% of calories from fat

• 15-20% of calories from protein 

Eating a higher ratio of carbohydrates in the week leading up to your race (also known as 

carbo-loading

 helps ensure your glycogen stores are full. And remember, these calories should come from high-quality, nutritious sources. For example, complex carbohydrates like oatmeal, brown rice, and sweet potatoes are preferable to cookies and candy. 

Although runners need to focus on carbohydrates, they also need adequate protein. Adding a scoop of Amandean collagen protein to coffee or a smoothie is an excellent way to get clean protein without extra fats or fillers. 

What to Eat the Morning of Your Marathon

On the day of your marathon, eat a light breakfast about 2-3 hours before the race starts. A small bowl of oatmeal or a bagel with peanut butter will suffice. Remember to stick with foods your body is accustomed to and can easily digest. 

Also, drink at least 16 ounces of fluid within the two-hour window before the race starts. Sports drinks can be consumed in combination with water during this time.

What to Eat During Your Marathon

While the goal is to consume 

30-60 g of carbohydrates per hour

, an easier way to break this down is to replenish every mile or 15 minutes. 
Check the race information ahead of time to see what will be offered at beverage stations along the course route, and also bring your own supply. Here's an example of how you can refuel each hour to get 45 g of carbs:

• 0:15 - Energy gel or chew + water

• 0:30 - 4 oz sports drink

• 0:45 - Energy gel or chew + water

• 1:00 - 4 oz sports drink

You can continue this pattern for the duration of your run or mix it up. Continue to drink water in proportion to how much you're sweating, which depends largely on the weather and how your body responds.

Your fueling doesn't stop when you cross the finish line. If someone hands you a beer, wait and drink it after you've put some good quality carbs and fluids in your system.

Follow up your race with a small meal or snack that includes carbohydrates and protein. A shake or smoothie with collagen protein is a great choice. Other options are bagels, yogurt, granola bars, and bananas. 

Now take a moment to celebrate this incredible accomplishment! 

Don't forget to visit the Amandean shop to find supplements that will help you stay injury-free, healthy, and performing at your optimal level.

Summary Points:

Like a car needs gasoline, your body needs plenty of carbs and fluids to keep you running smoothly.

Alternating water and carbohydrate-electrolyte beverages (like a sports drink) is critical during a marathon.

A good supplement routine throughout your training program and after your race will help your body repair and stay injury-free.

While the goal is to consume 30-60 g of carbohydrates per hour, an easier way to break this down is to replenish every mile or 15 minutes.

Article References:

1. Carbohydrates for training and competition. https://www.tandfonline.com/doi/full/10.1080/02640414.2011.585473?src=recsys
2. Fundamentals of glycogen metabolism for coaches and athletes. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019055/
3. American College of Sports Medicine position stand. Exercise and fluid replacement. https://pubmed.ncbi.nlm.nih.gov/9303999/
4. Fluids and hydration in prolonged endurance performance. https://pubmed.ncbi.nlm.nih.gov/15212747/