Our bodies need constant energy to function. However, they do not have unlimited energy reserves. In order to cover the needs, the body draws from both its reserves and the food we eat throughout the day.
What is the energy expenditure of mountain bikers?
Total energy expenditure over a day includes: Basic metabolism, energy expenditure related to workout and energy expenditure related to food digestion.
- Basic metabolism refers to the minimal energy expenditure for body function and maintenance. In standard conditions (on an empty stomach, at rest and at neutral temperature), the basic metabolism accounts for 50 to 70% of the daily energy expenditure. There is a significant inter-individual variability in basic metabolism, depending on the age, gender, body mass and level of physical activity. It may also change over a lifetime depending on our health status or physiologic status (repeated diets, thyroid disorders, etc).
- Energy expenditure related to physical activity includes daily activities, and sport and non-sport physical exercise. This expenditure may account for 15 to 30% of the total energy expenditure. Physical activity expenditure can vary with individuals. It may be increased based on the duration, intensity or type of physical activity. For MTB, it is considered that the average energy expenditure is 650kcal/hour for a man weighing 70kg.
- Energy expenditure related to food digestion accounts for 8 to 10% of the total energy expenditure.
It is worth noting that in addition to these three, another type of energy expenditure may be added in case of injury repair or healing, inflammation or infection.
Energy expenditures require energy intakes.
How to easily know whether you provide enough energy to your body? There is nothing better than weight variation.
A constant weight will depend on the balance between energy intakes and the total energy expenditures. Any excess intake that is not compensated by an increase in expenditures will lead to the storage of excess energy as fats, and therefore weight gain.
To give you some guidance, the French agency for food safety (Anses) set the following recommendations for daily energy intakes:
- 2400 to 2600 kcal per day for an adult men,
- 1800 to 2200 kcal per day for adult women.
These values need to be adapted since they do not take into account sport activities. For example, a mountain biker weighing 70kg who went cycling for 2 hours must have a 3800kcal intake to guarantee energy balance.
Energy intake and diet
Diet allows the body to produce the energy essential to achieve any performance and any movement.
The food we eat is broken down into macronutrients (proteins, carbohydrates and fats) and micronutrients (vitamins, minerals and trace elements). Some of them have an energy value.
- Carbohydrates: they account for 50 to 55% of the daily energy intake and 1g of carbohydrates provides 4 kcal.
- Proteins: they account for 10 to 15% of the daily energy intake and 1g of proteins provides 4 kcal.
- Lipids: they account for 35 to 40% of the daily energy intake and 1g of fat provides 9 kcal.
- Vitamins are essential to proper body function. They are involved at low concentrations in many vital processes. Vitamins do not provide any energy.
- Minerals and trace elements: daily intakes of mineral elements helps compensate the losses suffered by the body. A balanced and varied diet guarantees sufficient intake.