Energy and nutrient demand
As we explained in the last blog article, in order to perform its physiological processes normally or optimally, our body needs not only enough energy, but also the right nutrients. How much energy & and what nutrients in what quantity varies greatly from person to person.
Today we want to take a closer look at the basics of energy and nutrient requirements.
Straight to the facts !
- Daily energy needs are multifactorial and vary from person to person.
- It is composed of basal metabolic rate, physical activity, and food-induced thermogenesis.
- A calculation serves only as an approximate guide.
- The German Nutrition Society recommends consuming over 50% of calories in the form of carbohydrates and 30% in the form of fats, as well as 0.8 g of protein per kg of body weight.
How is our energy need composed?
It is important to know that energy needs not only vary from person to person, but also strongly depend on life circumstances. Both endogenous (age, gender, state of health) and exogenous factors (ambient temperature, physical activity) lead to a change in the daily calorie requirement.
In principle, the daily energy requirement or energy turnover is made up of 3 components:
Basal Metabolic Rate: basal metabolic rate is that energy required to maintain the basic functions of the body. For example, the energy needed by the heart to beat or by the lungs to breathe. If we were to spend 24 hours just lying in bed and not eating, our energy needs would consist only of our basal metabolic rate.
Physical activity: The energy needed for physical movement. The more we are in motion, the higher the energy requirement.
Food-induced thermogenesis: energy needed to digest our food.
In addition to these 3 main factors, stress (pain, mental stress) as well as thermoregulation (e.g., increasing body temperature when the ambient temperature is low) can also lead to increased energy consumption.
How do I calculate my own daily calorie demand?
To calculate your own energy requirements, you can use a simple formula. You calculate your basal metabolic rate and multiply it by the so-called Physical Activity Level (PAL).
The basal metabolic rate can be approximated with the formula 1 kcal/kg bw/hour. That is 24 x the own body weight results in the basal metabolic rate. For an example person with 70 kg this would be 1680 kcal. Now you have to multiply this with the correct PAL, which increases accordingly with increasing activity. The following PAL values can be used as an approximation:
The calculation becomes even more accurate if the respective PAL is multiplied by the exact number of hours of activity. Let’s assume that our 70 kg example person sleeps 8 hours, has a predominantly sedentary job, does little strenuous leisure activity, and does one hour of intense exercise every day.
Thus, her PAL would be calculated as follows: (8×0.95) + (15×1.4) + (1×2.4) : 24 = PAL = 1.29
Your basal metabolic rate of 1680 now needs to be multiplied by the PAL 1.29. This gives you a total energy expenditure of 2167 calories.
As already mentioned, the energy requirement depends on many factors. Thus, such a calculation serves only as an approximate guide. To estimate your energy needs more accurately, you can, for example, count calories for one to two weeks, stand on the scale every day and find out whether you are gaining or losing weight. Accordingly, the energy requirement can be adjusted.
Calorie counting in general can be very stressful and inflexible. Nevertheless, it makes sense to track your food at least for a short period of time, not only to get more information about your own calorie needs, but also to develop a feeling for how many calories individual foods contain.
How do I meet my energy needs?
Once you have calculated your energy requirements and, in the best case, adjusted them yourself, the question now arises as to how you should supply the energy. There are three different nutrients that provide energy. Carbohydrates, fats and proteins. Together they are called macronutrients. The question of the proportion of these nutrients differs depending on the type of diet. It is important to know that only fats and proteins are essential for us humans. It is imperative that we get them from our diet.
Carbohydrates, on the other hand, are the primary energy suppliers, but they are not essential because the body can also produce energy from protein and fat.
The reference values valid in Germany are published by the German Nutrition Society (DGE) together with the Austrian (ÖGE) and Swiss Nutrition Society (SGE). They form the D-A-CH reference values.
They recommend more than 50% of the energy intake to come from carbohydrates, more than 30% from fats and give an absolute value for proteins, namely 0.8 g /kg bw. These guideline values are comparable with those of international professional societies.
They not only publish guideline values for macronutrients, but also for the individual micronutrients (vitamins, minerals, etc.). These are available at https://www.dge.de/wissenschaft/referenzwerte/. To ensure that sufficient micronutrients are consumed, it makes sense to consume foods that are as nutrient-dense as possible. These are mainly unprocessed foods such as fruits, vegetables, whole grains, nuts, seeds, eggs, species-appropriate meat or seafood.
Text-Sources:
(1) Biesalski, H. (2018) Ernährungsmedizin. (5. Auflage) Georg Thieme Verlag.
(2) https://www.dge.de/wissenschaft/referenzwerte/
(3) Suchorski, N. (2019) Anwendung der D-A-CH Referenzwerte für die Nährstoffzufuhr. Ernährung & Medizin. Georg Thieme Verlag.
(4) Dietger, M. (2018) Fit und gesund von 1 bis Hundert. (4. Auflage) Springer Verlag.
Image-Sources:
(5) Dietger, M. (2018) Fit und gesund von 1 bis Hundert. (4. Auflage) Springer Verlag.
