Training Marathon
Training to run a marathon


Marathon Nutrition

Proper nutrition is one of the key factors in obtaining and maintaining fast and steady speed . The nutritional concern of an athlete should focus on both short-term energy provision and long-term health and optimal functioning of the body. The primary concern for short term is with the nutrients that provide energy for muscular contraction and for the long term eating foods that only provide adequate vitamin and minerals.

Our body cannot move without muscle contraction and for that to happen there has to be a relatively constant supply of chemical energy available to the muscle called ATP (Adenosine Triphosphate). ATP is to the muscle what gasoline is to your car’s engine and in order for the muscles to produce ATP it needs carbohydrates, fats, or protein. Although all three energy nutrients can be used to produce ATP, as long as there is enough carbohydrates and fats in the diet, protein is not used to make significant amounts ATP. Protein is mainly used for building and repairing muscle and other tissues.

Besides carbohydrates, fats, and protein (Sometimes called energy or caloric nutrients because they provide source of energy that is eventually transformed into ATP) The body also needs vitamins, minerals, and water which are essential for all the chemical reactions that produce energy. Without adequate amounts of vitamins, minerals, and water, all the carbohydrates, fats and proteins would be almost useless.

Caloric nutrients

As a percentage of total calories consumed:

  • Protein should comprise 15% of energy intake.
  • Fats should comprise 20-25%, and
  • Carbohydrates should be the remainder: 60-65% of total calories.

Ideally, decrease fats even more and increase carbohydrates even higher. Protein is the constant in this relationship and the carbohydrates and fats are inversely related. Carbohydrate consumption should go up as fat consumption (as a percentage of total calories) goes down.

In high level effort, your body increases the proportion of carbohydrates usage and decrease the proportion of fats. In long distance events athletes usually burn about 70% carbohydrates and 30% fat during the first hour before their carbohydrates start to deplete. A shorter & fast pace activity could use 95% carbohydrates and only 5% fats. Therefore, the basic rule is the higher the intensity, the more carbohydrates you use.

If athletes run out of carbohydrates. the consequence is a phenomenon often called “hitting the wall” wherein, they have to slow their pace and the work becomes much more difficult. When fats are the major source from which to make ATP, you can continue with your activity, just not as fast but at a reduced speed.

Training increases your ability to use fats at higher intensities. This is a very advantageous adaptation for marathoners because it allows to conserve carbohydrates for later in the run and they are not as likely to run out of carbohydrates.

Diet and Weight
Eating a high-carbohydrate diet increases the proportion of carbohydrates use. Eating a high-fat diet increases the proportion of fats use. If your diet consists of a high proportion of carbohydrates on a regular basis, then you will burn more carbohydrates for energy all the time

In addition to eating adequate amounts of protein and carbohydrates, another key to optimal nutrition is eating the proper amount of total calories. The key to maintain or lose weight  is a combination of caloric reduction and increase in caloric expenditure.

  • 1 gram of carbohydrate and protein = 4 kilocalories of energy and
  • 1 gram of fat = 9 kilocalories of energy

The amount of exercise you will be doing tends to stimulate the appetite which is another important reason to decrease consumption of fats and increase carbohydrates consumption.