HOW TO CALCULATE BASAL METABOLISM
Throughout our lives we will constantly be setting new goals and objectives, one of the most common is the improvement in nutrition. Whether for aesthetic purposes (usually the most common) or for health purposes. The beginning of a diet is a constant that is usually present and It is important to know the recommended caloric restriction, as well as to have basic knowledge about basal metabolism and diet. before starting a diet, although it is better if it is with the help of professionals since it can be dangerous and harmful to our health.
Before starting a diet there are several questions.
- When to start?
- What type of diet should I follow? (Ketogenic, Atkins, LowCarb)
- How long will it take to reach my goal?
- Does this have to be for life?
- Will it work?
- Will I go hungry?
However, there is one issue that I consider should be the initial pillar and perhaps the most important.
The importance of Basal Metabolism
It is the amount of energy our body needs to maintain its vital functions - breathing, heartbeat, hormonal secretion, etc.
And at this point you might ask yourself Why ? If I just want to know how much lettuce I should eat and when. There's a phrase we like to use that can put the importance of this element into context: "A system that isn't understood can't be evaluated or improved." What are we trying to achieve with this?
Let's make a simple comparison with something that we all have more in mind, a car.
Imagine you're about to embark on a long trip and there are no gas stations along the way. The car you have at your disposal is out of gas, so you decide to go to a gas station to fill up, but you don't know how much gas the tank holds. It will be impossible for you to perform an optimal charge that guarantees you can cover the distance (at least until the next available charging point) if you don't know the capacity of that tank.
Now imagine you read the manual and find out that the gas tank has a maximum capacity of 50 liters. Just enough to get to the next gas station.
Is in At this moment 3 options are presented to you:
- I fill the tank with less than 50 liters, risking not reaching my destination and possibly causing the car to break down if I don't provide at least enough fuel.
- I fill the tank with 50 liters and travel peacefully.
- I panic and fill the tank with 50 liters and some bottles that I will carry in the trunk, having to endure the infernal smell and the risk that this entails.
Just like the car in the example, our body requires a specific amount of energy to carry out its basic functions “Basal Metabolism”, even if we are on a calorie-restricted diet.
We cannot know how much to restrict if we do not even know an estimate of what our body needs (at least the minimum amount to get to the next gas station or, better said, the amount sufficient to maintain functions such as the heartbeat; after all, to be able to "diet" you have to be alive).
And now that we know What is Basal Metabolism and the importance of knowing it, Let's move on to the next point. The manual tells us how many liters our tank holds.
There are various methods to know it Let's go through the most basic ones and get to the most complex and precise ones.
How to calculate energy expenditure?
There are different formulas (more or less) to calculate basal energy expenditure, so don't worry, even if you're bad at math. They're simple! They're as follows:
Harris-Benedict Basal Metabolism Formula
(I.e. GEB = 66.473+13.752xp (weight in kg)+5.003xa (height in cm)-6.755xe (age in years)
♀ GEB = 655.096+9.563xp +1.85xa-4.676xe
Each number has its reason for being and explanation, but that is not the objective of this video.
Let's take an example of a woman weighing 63 kg, 165 cm tall, and 29 years old.
♀ GEB = 655.096+9.563x 63+1.85×165-4.676×29 = 1427
There is a revision of this formula made by Harris Benedict for Mifflin and St Jeor in 1990.
(I.e. GEB = (10 x weight in kg) + (6,25 x height in cm) – (5 x age in years) + 5
♀ GEB = (10 x weight in kg) + (6,25 x height in cm) – (5 x age in years) – 161
This formula may be a little more harmonious or easier to use for you.
Historically, dietitians have used these formulas to estimate Basal Metabolism, we must take into account that There are studies that have found that these equations can overestimate or underestimate the energy requirement.; It can have a variability of 20% or a deviation of 200 Kcal, which although slight, is important, as it can promote weight gain in adults.
Cunningham's Basal Metabolism Equation
It is calculated using the fat-free mass. Basal metabolic rate (kcal/day) = Fat-free mass (g) x 21,6 + 370
To use this equation it is necessary, as previously mentioned, to know the fat-free mass, which can be obtained by the methods described in the following method.
How can we measure free mass?
- La absorptiometry dual-energy X-ray (DEXA)
- La anthropometry (or measuring skin folds) which is usually the most used method due to its ease of application as it does not require any equipment other than a caliper and at the same time the most studied and contrasted with more precise methods, however it can be a little invasive as it requires having the person with some parts of the body uncovered and pinching the skin folds.
We're almost at the end. Today is proving to be a long one, but very, very useful, especially after the Christmas holidays.
Bioelectrical impedance
In recent years, it has become more widespread because it is noninvasive, quick to apply, low cost, and safe. There are several commercial brands, the most accurate in my opinion being the In-Body brand due to its electrode system. (I will not go into this field as it can be broad and biased.)
In the end, you can use the method that best suits you and makes sense to you. For example, using calipers requires a specific learning process that's difficult to apply on your own, while even the most inexpensive scale can at least give you some guidance.
Within the section on Indirect Calorimetry, let's talk about O2 consumption.
Which is governed by the assumption that the chemical energy of a substrate is obtained in the organism after its complete oxidation with the consequent consumption of oxygen and release of carbon dioxide and water, It is possible to estimate the total amount of heat produced in the body by determining the volume of both gases.In simple terms, chickens in per chickens out, the more O2 you consume, the more energy you need.
There is evidence that this method is the most accurate. Direct calorimetry methods exist, but due to their complexity and difficulty of application, they contribute little to this video.
Well now that you know What is basal metabolism and how is it measured? Let's move on to the practical part, which is probably the one that interests you the most. Although limit caloric intake has a correct basis for weight loss we must take into account the basal metabolism, in a person who has many energy reserves (obesity) The body can carry out adaptation mechanisms to obtain the restricted energy from the diet from reserves and thus lose fat.
But what if our goal is different? how to gain muscle mass or perform body recomposition (losing fat and continuing to gain muscle), what happens if I am a highly active person and the cost of performing a significant calorie restriction could mean that I don't make it to the next gas station despite my reserves.
It's here where knowing at least that basal metabolism exists will keep you at a distance or at least generate some skepticism When a professional suggests a “severe” calorie restriction, something that happens very frequently. And from here more points are derived, When there is a significant caloric deficit, people often go hungry., seeing a diet as something horrible that you want to end quickly and that at the end of the road generates an unsustainable change with significant rebounds. Since When your body perceives nutrient shortages, it becomes efficient at storing fat.This is a very broad topic and we'll cover it in another video. Sorry for the slight deviation.
Botton line
– Do I need to know my basal metabolism?
A- At least knowing that it exists will allow me to adjust my diet to my goals and preferences.
-Can basal metabolism be calculated accurately and precisely?
A- Yes, but in most of the methods available on a daily basis the estimates are not that exact, but at least they allow you to have an approximation and not go to extremes.
– Is my basal metabolism always the same?
A- No, and it depends on several variables, such as lean mass, which evolves, training age, and illness. That's why it should be adjusted from time to time.
– Once I know my basal metabolism, should I restrict myself to it?
A- Again, NO, as in the following videos we'll explain how to adjust according to your activity level. But before adjusting the amount of food, we had to know what we needed first.
– Is calorie measurement everything?
A- No, it's a longer topic. The simple answer is that 1500 calories of chocolate is not the same as a varied diet, so we shouldn't base our decisions solely on this number.
We hope this video has laid the groundwork for your calorie needs. This information is in no way intended to replace consultation with a professional., is only intended to give you tools to understand the basis behind each diet prescription. If this raises any further questions, we invite you to leave them in the comments section, or if you'd prefer someone to give you personalized advice. contact us.
