OUR COMPREHENSIVE MARATHON ENERGY AND FLUID INTAKE GUIDE

Our comprehensive guide will help you prepare and implement a successful nutrition and hydration plan for your next marathon.

When people talk about preparing for a marathon, their focus is usually heavily on the training they do. Nutritional preparation is talked about far less and is often a secondary consideration for many athletes. As with many sports and events, the difference between a personal best and failing to finish the race can come down to consuming the right (or wrong) foods and drinks in appropriate (or inappropriate) quantities. Many of the most common reasons athletes give for a poor race are related to nutrition, such as: e.g. lack of energy, stomach problems or dehydration.

This guide is designed to prepare you for a marathon from a nutritional perspective, from planning in the weeks leading up to the race right through to the race.

CARBOHYDRATES FOR SUSTAINABLE ENERGY

The human body has two main sources of fuel: fat and carbohydrates. Both are stored in the body and act as two separate “fuel tanks” that can provide energy for exercise. Carbohydrates can be used quickly by the body and provide energy much faster than fat. Using fat also requires more oxygen and when oxygen supply is limited, carbohydrates can still be used while fat cannot.

Therefore, carbohydrates are consumed in much larger quantities than fat when exercise intensity is very high and energy intake needs to be rapid. In contrast, fat is an ideal source of energy for low- to moderate-intensity exercises where energy requirements are lower. One of the main differences between the two fuel sources is their storage.

HOW CARBOHYDRATES ARE STORED

Carbohydrates are stored as glycogen, which is found in the liver and muscles. The glycogen stored in the muscles is used by the muscle in which it is located when there is a high energy demand. Therefore, when running, the glycogen stored in the thigh muscles is used up much more quickly than the glycogen in the arms. All muscles in the body combined can store 400 to 800 g of glycogen, which depends on body size and the amount of carbohydrates consumed.

Liver glycogen is stored in much smaller amounts, around 80g, which varies less from person to person. Glycogen stored in the liver is broken down into glucose and transported in the blood to where it is needed, including organs such as the brain and kidneys, but also muscles during physical activity.

HOW FATS ARE STORED

Fat is stored primarily in adipose tissue, which is located throughout the body. Even for most slim people who have a relatively low body fat percentage, the amount of energy stored in fatty tissue is enormous. Fat is also found in much smaller amounts in muscles, but the majority of fat in the body is in adipose tissue, which is measured in kilograms.

Even in very lean people, fat stores number tens of thousands (if not hundreds of thousands) of calories, while carbohydrate stores (as glycogen), even with high glycogen stores, only number a few thousand. Fat stores are virtually unlimited in terms of energy needs for exercise, while carbohydrate stores can limit endurance training.

AGAINST THE WALL

Many runners are familiar with the experience of “hitting the wall,” which essentially occurs when glycogen stores are running low and available fuel cannot produce energy quickly enough to sustain high-intensity training. Glycogen stores are usually sufficient to support 2.5 to 3 hours of exercise, depending on the training intensity and the amount of glycogen stores. In a marathon, "hitting the wall" often occurs after about 20 miles (32 km).

Consuming carbohydrates before and during exercise can help prolong performance and delay glycogen breakdown. Unlike consuming additional carbohydrates during exercise, consuming fat does not improve exercise performance because fat intake is not a restriction like carbohydrates are. Therefore, ensuring high carbohydrate availability is crucial for endurance training performance.

TRAIN YOUR GUT FOR A MARATHON

Just as you can (and should) train your body for the event you are planning, you can (and should) train your body for the foods, beverages, and nutritional practices you plan to use. Good nutrition has the potential to improve marathon performance in a number of ways, but if used improperly, even the ideal diet can cause problems if you're not used to it.

Consuming food or drink during exercise triggers gastrointestinal problems for some runners, including symptoms such as reflux, heartburn, bloating, vomiting, bloating, stitches and diarrhea. If you experience such symptoms while training and consuming carbohydrates, it is likely that the same symptoms will also occur during your marathon.

Practicing with the carbohydrate amounts, type of carbohydrate, and format (gel, drink, bar) you want to use during your race training can help reduce symptoms and maximize the amount of carbohydrates you can consume .