The Science of Eating Right for Marathon Success

A runner in a race running with pink background. Bushwick Bites. The Science of Eating Right for Marathon Success. Scott Keatley

It’s Fall marathon time! As thousands of feet pound the asphalt, we’re reminded that marathons are not just feats of physical endurance but also triumphs of meticulous planning and discipline. While much focus is given to perfecting stride and building cardiovascular stamina, the role of nutrition in a marathoner’s journey is often underestimated. Yet, food and fluids are the literal fuel that powers this formidable 26.2-mile endeavor.

Figure out your start time and work backwards. In the final 72 hours leading up to the marathon, there’s a strategy that many seasoned runners employ—carbohydrate loading. The scientific foundation for this lies in the body’s biochemistry. Carbohydrates are the most efficient source of energy, being readily converted into glucose, which fuels our muscles and brain during moderate to high-intensity exercise. By increasing carbohydrate intake in the days before the marathon, runners aim to maximize the storage of glycogen in their muscles and liver.

Here’s the nitty-gritty: Glucose is the stored form of glycogen. It acts as a reserve tank of energy that the body taps into during extended physical activity. When these reserves are depleted, one hits the dreaded ‘wall,’ characterized by a sudden feeling of fatigue and a marked decline in performance. By topping off glycogen stores before the race, athletes aim to delay this onset of exhaustion for as long as possible.

On the morning of the marathon, it might be surprising to hear that consuming about 900 calories from the time one wakes up until the starting gun is highly advisable. When exercise stretches beyond 60-90 minutes, the body’s internal fuel stores are not sufficient. The breakfast aims to provide a significant but easily digestible infusion of carbohydrates, such as fruits or energy bars.

In addition, a source of protein, like almonds or a protein shake, helps to slow down gastric emptying. This means you go into the race feeling full but not bloated. Proteins have a slower transit time through the digestive system, giving a more sustained release of energy, making it a key component of the pre-race meal.

In-race nutrition offers its challenges. The body needs a continued supply of energy, but the gastrointestinal system isn’t as efficient during exercise. Simplicity is key, and this is where energy gels and sports drinks with simple sugars prove invaluable.

Research indicates that a mix of glucose and fructose allows for higher absorption rates of carbohydrates—up to 90 grams per hour. This is a crucial data point because it underscores the importance of the type of carbohydrate consumed during the race. Most standard sports gels and drinks often incorporate this mix, allowing for quicker absorption and sustained energy.

Also, a moderate amount of caffeine in these gels can improve athletic performance by enhancing focus and potentially aiding the body in burning fats for energy. This can be particularly advantageous in conserving precious glycogen stores for later stages of the race.

But let’s not forget hydration. While water is essential, electrolytes should not be ignored. These charged particles help maintain cellular fluid balance and are lost in sweat. However, overhydration can lead to hyponatremia, a life-threatening drop in blood sodium levels. As in all things, balance is crucial.

Once the finish line is crossed, the focus should swiftly shift to recovery. Consuming a mix of carbohydrates and protein within 30 minutes after the race is recommended for optimal recovery. This blend capitalizes on the body’s heightened insulin sensitivity post-exercise, driving glucose and amino acids into muscle cells for repair and energy restoration. If the idea of whole foods doesn’t appeal to you at this point, liquid options like chocolate milk or a protein shake are excellent substitutes.

Marathon running is not just about the miles logged in training; it’s a complex interplay of multiple variables, with nutrition playing a vital role. From carbohydrate loading to in-race fueling strategies and post-race recovery, each dietary decision is a calculated move based on sound scientific principles.

Understanding the ‘why’ behind these actions not only equips runners with valuable knowledge but also provides the much-needed rationale for seemingly odd dietary choices. In the end, knowing the science of what to eat, when to eat, and how much to eat can make all the difference between an excruciating crawl to the finish line and a triumphant, arms-raised sprint.

Good luck out there!

Author: Scott Keatley