Nutrition encompasses the set of voluntary and conscious actions that lead to the selection, preparation, and consumption of food. These actions are clearly linked to socio-cultural and economic environments and largely determine nutritional habits.
The concept of nutrition refers to the involuntary processes that occur after ingesting food, i.e., absorption (into the bloodstream), metabolism (chemical transformations at a cellular level), and excretion (elimination from the body). Adequate nutrition is that which covers:
- Energy requirements through the intake of energy-providing macronutrients (carbohydrates –CHOs–, fats, and proteins) in the right proportions.
- The needs of non-energy-providing micronutrients (vitamins and minerals).
- Proper hydration (water intake).
We need to eat to meet our energy requirements (energy expenditure), which are directly related to our level of physical activity. However, other factors also influence energy expenditure.
In winter sports, the energy consumption associated with training depends mainly on four factors:
- The friction of the board against the snow.
- Shifting body weight uphill and on flat terrain.
- The acceleration of different body segments and the centre of gravity.
- Overcoming air or wind resistance.
Moreover, the relative importance of these factors in energy consumption during snowboarding depends on technique and style (halfpipe, alpine, freeride), the level of technical coordination, the type of slope, snow conditions, and speed. This makes it difficult to quantify the energy expenditure associated with a winter sport.
In the human body, energy expenditure is directly related to muscle mass (active mass). Athletes who weigh more and have greater muscle mass consume more energy at rest and during exercise than their lighter counterparts. Generally, from adolescence onward, women have a higher percentage of body fat and a lower proportion of muscle mass, so their caloric requirements will be lower.
Exercise intensity and duration determine the primary fuel source used by muscles. Typically, the higher the exercise intensity, the greater the reliance on muscle and liver glycogen (the stored form of carbohydrates) for energy. Sustaining high-intensity training requires burning carbohydrates. Glycogen stores are limited, so the longer the moderate- or high-intensity exercise (depleting glycogen), the more likely the body is to use fat reserves. Conversely, during low-intensity exercise, fats become the primary fuel source.
Endurance training improves fat utilisation, reducing carbohydrate reliance at the same exercise intensity. This adaptation helps conserve glycogen reserves. Additionally, endurance training enhances the muscle’s ability to store glycogen—provided the post-training diet supplies the necessary carbohydrates for recovery.
Pregnancy and lactation are conditions requiring additional energy for tissue growth and/or mammary gland secretion. Finally, when training in cold temperatures, the rise in core body temperature is reduced, and internal heat production increases through greater substrate utilisation.
When shivering occurs (involuntary rhythmic contraction), energy expenditure is estimated to increase by 2.5 times. In this scenario, carbohydrate oxidation rises nearly sixfold. Furthermore, in cold conditions, heightened sympathetic-adrenal activation (nerve stimulation of the adrenal glands) increases blood adrenaline levels during low-temperature exercise. This accelerates muscle glycogen breakdown and liver glucose production. Thus, carbohydrate utilisation rises during cold-weather training, necessitating replenishment via a high-carbohydrate diet.
