Carbohydrate, fat and protein: why each fuel has a role in endurance sport

Having a lot of energy stored in the body does not mean being able to use it at the necessary speed to maintain a certain effort. This distinction is the key to chapter 2.

Suzanne Girard Eberle explains how carbohydrates, fats and proteins participate in the activity and why food needs to keep up with demand. The interest is not to choose a winning fuel, but to understand the role of each one.

Different reserves perform different tasks

The body stores carbohydrates in the form of glycogen, mainly in the liver and muscles. These reserves do not function as a single pantry without divisions.

The muscle glycogen meets the work of the muscles in which it is stored. The liver participates in the maintenance of circulating glucose. Feeding and exercise modify the state of these reserves throughout the day.

Therefore, arriving at training after many hours without eating and starting a session after organized meals are different situations, even if the athlete has the same weight on both occasions.

The planning seeks to offer available fuel when it will be necessary, in addition to sufficient energy in total.

Abundant fat does not guarantee the desired pace

The fat represents a large reserve, but its participation depends on the intensity and conditions of the effort. As the demand for rapid energy grows, the availability of carbohydrates becomes important.

The teaching is to distinguish the size of the reservation and delivery fee. A large reservoir does not solve a task when the available output does not provide energy at the required speed.

This idea helps to understand why an athlete may need to greatly reduce the pace even with body fat. The difficulty does not prove that all its energy is gone; there may be incompatibility between the energy available for that effort and the intensity desired.

Training changes fuel use

The author explains that adaptation to endurance modifies the ability to use energy. The trained athlete can better manage certain intensities and preserve reserves differently.

This does not mean that more training is available. The preparation and the fueling complement each other: an adapted body still needs to deal with the requested work and the reservations present.

It is useful to observe the duration and intensity together. A short and demanding session can have a relevant demand of carbohydrates; a long and quiet output presents another combination of challenges.

Protein has important work besides providing calories

Proteins participate in the construction and maintenance of tissues and many functions of the organism. In the chapter, the concern is to prevent the search for energy from leaving these tasks discovered.

When feeding is insufficient, adding protein alone does not solve the whole problem. The athlete continues to need energy to train and recover.

A dish with a large protein portion and almost no energy base is not suitable for every session simply because it contains a lot of protein.

The question needs to change how much more protein I can eat for what tasks my feeding needs to attend today.

Percents can hide the actual amount

The same proportion of carbohydrates represents different amounts in diets with different energy totals. The calculation helps to understand why saying that the diet has a certain percentage may be insufficient.

Editorial example: 50% of 2,000 kcal corresponds to 1,000 kcal of carbohydrates, or approximately 250 g. The same proportion in 3000 kcal corresponds to about 375 g. The percentage is equal, but there is difference of 125 g.

As carbohydrates and proteins provide approximately 4 kcal per gram, this type of conversion helps to check the meaning of numbers. It does not in itself define how much a person needs to consume.

The book also uses grams per kilogram in its references. This format makes the amount related to body size more visible, but still needs training context.

The expense of the clock is not a replacement order

The chapter teaches how to meet energy needs; hence it is not necessary to replace each calorie estimated by the device during the session.

The work uses body reserves and ingested fuel. The intake needs to be viable and tolerable. The total session calculation and the rate of consumption during movement respond to different problems.

This point will be important in long competitions: trying to eat at the same speed as a high expense can produce an impossible plan to execute.

Recovery closes calculation

At the end of the session, part of the task is to reorganize the reserves used and offer conditions for the next day. The closer the sessions are, the more relevant it becomes not to leave this stage entirely at random.

The common error is to think only of the training that ended. An activity performed at the end of the day may influence the energy availability of early training the following morning.

Sufficient feeding throughout routine, fueling when needed and recovery function as parts of a sequence.

Editorial application: Why does the second training get worse?

Consider an athlete who completes the first session well, makes small meals and arrives without disposition to the second. He can interpret the fall as lack of conditioning and try to compensate with more stimulus.

Before that, is it worth examining the interval: was there a meal? Was the quantity accompanied by the work? Was there a real opportunity to eat? Was the recovery planned?

This example does not determine a clinical cause. It shows how fuel knowledge improves questions.

The Teaching That Stays

Carbohydrate, fat and protein are not competitors who need to eliminate each other. They perform different functions, and the organization of feeding depends on what the athlete intends to do.

The chapter gives the reader a way to reason: recognize the reserves, understand the speed required by the effort and build a routine that allows to use and recompose energy. In the following applications, this logic will be translated into schedules, food, products and logistics.

Primary reference: EBERLE, Suzanne Girard. Endurance Sports Nutrition. 2nd ed. Human Kinetics, 2007. Cap. 2, “Meeting Energy Needs of Distance Demands”. Explanatory summary in our own words. Numerical examples and situations identified as editorials are from Enduran-se.

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