Nutrition for trekking
What follows is the translation of the original Italian article by Paola Salgarelli, biologist nutritionist, specialist in Food Science:
Trekking is an activity characterized by a prolonged effort, more or less intense according to the type of path we take. For this reason it is really important to follow a specific nutrition before, during and after any excursion, to avoid any physical problem and having enough energy to continue the activity to the end.
To understand what can be the most suitable diet, let’s look at what the main functions of the macronutrients of our daily food are:
- Carbohydrates, that in the Mediterranean diet represent the 55-60% of the daily caloric intake, have mainly an energetic function, but can be also stored as a reserve (glycogen). Carbs can be simple (for example: glucose, fructose, sucrose), with the characteristic of being quickly absorbed by our body and provide energy immediately, or complex (for example: starch), which release energy slowly. Complex carbohydrates allow to have energy for longer time while your body is making a particular effort, because they need to be transformed in simple carbohydrates before being used.
- Proteins, unlike carbohydrates, have mainly a “plastic” function, which means they are needed to grow and repair tissues, but in extreme conditions (starving or prolonged efforts) they can also have an energetic function.
- Fats or lipids, instead, are useful as a energy reserve, but they also have other basic functions among which the transportation of some proteins, the thermal insulation or the formation of the structure of cellular membranes.
The macronutrients are our energy substrate and are used in a different way according to the type of activity:
- if we are speaking about physical short term activity with low intensity our body uses in the same measure carbohydrates and fats.
- in physical activities with low intensity but medium duration (about 1 hour) there is a reduction of the reserve of carbohydrates (so the glycogen) and a bigger utilization of lipids.
- in physical activity with high intensity and long duration there is utilization of lipids and the exhaustion of glycogen after about 2 hours.
The problem is not to be undervalued because in the sport of endurance and intensity, the stock of glycogen can be exhausted more rapidly, so that a part of the energetic source will be obtained from the degradation of proteins (gluconeogenesis), with a damage on the muscular tissue. Therefore, in this cases it is important to follow a precise nutritional timing.
- before starting it is necessary an adequate intake of food, mainly complex carbs, but also in part simple sugars (to have immediately an energy load). Let’s think that this first meal is breakfast, the most suitable food is, for example, toasted whole bread with jam, with a cup of milk or yogurt sweetened with honey. In addition, dry fruit and/or fresh fruit, rich in vitamins and mineral salts. Dried fruit, moreover, is useful to reach a good intake of calories, to have the “fuel” needed to make the physical effort you are about to make.
- during the activity small and frequent light meal are suggested, preferring carbohydrates with low glycemic index (as for example bread and bakery products), that allows you to have energy slowly during time. Since this food is not easy to consume during an excursion, a great alternative is using Bivo, that contains carbohydrates coming from low glycemic index food (like for example oat flour). Bivo is also very easy to digest and can be drunk during an excursion, allowing a constant hydration.
- after the activity we need to integrate the calories we have consumed with a complete meal that can allow your body to recover mainly carbohydrates and proteins.
Hydration during an excursion. Often we undervalue the need to constantly integrate liquids during trekking, to avoid to lose mineral salts and bring our body to a collapse. During excursion activities there is intense sweating which makes our body lose until 2 litres of liquids per hours, and even the increase in the breath frequency can make you lose more liquids as water vapour. For this reason every half an hour it is necessary to drink water, better if with the addition of mineral salts. The introduction of liquids, moreover, brings to an improvement in the performance.
What should I drink? It is suggested to drink isotonic or slightly hypotonic drinks (which means with identical osmotic pressure or a little lower osmotic pressure than the plasma).
A great “home made” drink is the following:
- 1 litre of water,
- the juice of 2 oranges,
- a pinch of salt,
- 2 spoons of fructose.
Like we said before, also the use of Bivo during an excursion can help to obtain the right hydration.
Non recommended drinks are instead those based on alcohol because they alter the reaction timing, the balance and coordination of movements and cause a higher lose of heat, since they create a pheripheral vasodilatation.
To conclude, we should remember that food is our fuel, that allows to the man-machine to work at its best, so it is fundamental to build the energy reserves we need during physical activity. Therefore, a careful outdoor enthusiast should learn not only to study which paths to go and how to complete the planned adventure, but also to plan the food stocks. And let’s remember that Bivo can be of great help because it provides slow releasing energy, it contains vitamins and mineral salts, it rehydrates, all of this with little weight and space in the backpack!
Paola Salgarelli, Biologist Nutritionist, specialist in Food Science