You may hear people talk about metabolism when discussing health, weight, and nutrition. It can be low, high, slow or fast, but what exactly does it mean? What is metabolism?
Metabolism is the set of chemical reactions that occur in the cells of living organisms to maintain life. Therefore, it is a set of processes, not a single process. Metabolic processes are varied, leading to growth and reproduction and allowing living organisms to maintain their structures and respond to the environment around them. Now that you know this, you will understand why it is at least imprecise to speak of metabolism as a single process that can be increased or decreased. Understanding that it is a set, the question is what processes are increased or decreased?
All chemical reactions that occur in living organisms, from digestion to the transport of substances from cell to cell, can be part of metabolism.
Metabolism
Okay, we could reduce the concept to metabolism as the set of chemical reactions that converts food into energy in our body. It is worth mentioning that these chemical reactions of metabolism are controlled by specific proteins of the organism. It starts to complicate the concept, right? The ultimate purpose of metabolism is to run cellular processes by converting fuel or food into energy and to eradicate nitrogenous waste. Why nitrogen-containing compounds specifically? Because these compounds are toxic to us. Some examples of this type of molecule are urea and ammonia.
Metabolism processes are also responsible for converting food or fuel into carbohydrates, nucleic acids, proteins, and lipid building blocks.
How does metabolism work?
The reactions of metabolism can be grouped into two large groups : catabolism and anabolism. Catabolism is the breakdown of organic matter, and anabolism uses energy to build cell components, such as proteins and nucleic acids.
In the metabolic process, that is, in the reactions that are part of these metabolic functions, chemical reactions are organized in metabolic pathways . In other words, we can group the reactions of our organism according to their specific functions and the path of certain substances, either until their creation or until their decomposition. Thus, we speak of metabolic pathways, such as the glucose metabolic pathway, for example. What all metabolic pathways tend to have in common is that one chemical is converted to another through a series of intermediate steps. These reactions are facilitated by enzymes that act as catalysts and help the reactions to occur, and usually to do so more quickly. Therefore, enzymes are proteins that play an important role in this regard, and these reactions cannot take place without them, as they help regulate metabolic pathways and usually influence the rate. The rate at which the process of metabolism occurs is known as the metabolic rate .
Basal metabolic rate and resting metabolic rate
The body uses energy for crucial activities like digestion and breathing. Metabolism regulates the use of energy to perform these functions. Both the basal metabolic rate (BMR or BMR) and the resting metabolic rate (RMR) calculate the amount of energy in the form of calories that the body needs to perform its functions efficiently .
Research shows that BMR helps calculate the fewest number of calories the body needs for essential functions. These functions may include digesting food, growing hair and skin, maintaining chemical levels, pumping blood throughout the body, breathing, and maintaining body temperature. It has been estimated that BMR tends to drive 70% of the calories an individual burns every 24 hours.
Now, one of the important questions that arise in a person’s mind while learning about metabolism is what it means to have a low Resting Metabolic Rate (RMR). The name shows that something is at rest, and the rate is calculated. Correct, when the body is at complete rest, the total number of calories burned at that time is the resting metabolic rate.
Studies suggest that RMR supports blood circulation, respiration, basic neurological functions, and organ functions. It is proportional to lean body mass and reduces about 0.01 kcal/min for every 1% increase in body fat.
We must keep in mind that many factors affect the resting metabolic rate , including age, genetics, sleep, calorie intake, etc.
How is the Basal Metabolic Rate calculated in adults?
As we have mentioned, the basal metabolic rate (BMR) is the minimum amount of energy that your body needs to survive carrying out basic functions , such as breathing, blinking, filtering blood, regulating body temperature or synthesizing hormones.
Even if you are completely at rest, your body continues to work to carry out those vital functions necessary for the proper functioning of your body.
There are many formulas for calculating BMR , but one of the most widely used around the world is Harris Benedict ‘s formula described in 1919, revised by Mifflin and St Jeor in 1990.
The calculation is as follows:
- Men BMR = (10 x weight in Kg) + (6.25 x height in cm) – (5 x age in years) + 5
- Women BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) – 161
Depending on the type of activity you do , the minimum amount of energy or the number of calories you need will vary according to these parameters:
- Little or no exercise = BMR x 1.2.
- Light exercise (1 – 3 days per week) = BMR x 1.375.
- Moderate exercise (3 – 5 days per week) = BMR x 1.55.
- Vigorous exercise (6 – 7 days per week) = BMR x 1.725.
- Very hard exercise (twice a day, very hard workouts) = BMR x 1.9.
High and Low Metabolism – Introduction and Difference
Looking at the terms “high metabolism” and “low metabolism”, it is now easier to understand that this is a metabolic rate that we can calculate. That is, something that is related to the speed of the processes that, as we mentioned, is also related to the activity of the enzymes that influence the processes, among other factors.
Be careful because if you haven’t noticed yet, the following may surprise you. If we look at the formulas for calculating Basal Metabolic Rate, the higher the weight, the higher the result . Therefore, metabolism increases with obesity. This is because our body has to work harder the more cells or processes we require. On the other hand, it is also true that many findings relate that people with a high metabolism are more likely to lose weight and burn calories than people with a low metabolism. Perhaps this is why it is easier to lose weight the more weight there is to lose.
Of course, there are more factors that can affect metabolic rate , such as weight, gender, age, hormonal function, and physical activity levels.
How to improve your metabolic health?
Let’s explore some health-focused concepts to learn how you can burn more calories and improve your metabolism.
Drink more water: Dehydration slows down your metabolism, and if you already have a low metabolism, then that’s a cause for trouble. You must stay well hydrated, as water plays an important role in this regard. The body needs water to process calories. The study shows that people with a low metabolism tend to gain more weight if they drink four glasses of water. Those who drink eight or more glasses of water tend to burn more calories and maintain a healthy weight. Therefore, try to drink water more often, especially before half an hour of your meal.
The power of protein: When the body needs to digest protein, it burns more calories. You may be overweight due to frequent intake of refined carbohydrates. Therefore, you can boost your metabolism by substituting protein for carbohydrates, so your body can burn more calories and help you lose weight instantly. Beef, fish, tofu, turkey, white meat chicken, beans, nuts, eggs, and low-fat dairy products are high-protein foods. They should be consumed by everyone who is overweight and has a low metabolism.
A smart snack: Make sure you don’t believe the myth of eating less or not at all to lose weight. If your metabolism is slow, it won’t help you at all. However, eating healthy and in larger quantities can help you lose weight. Metabolism slows down when you eat a large portion of snacks and don’t eat for a long time. The metabolism does not work properly during all this time. You can keep your metabolism active and fast by eating every 3-4 hours in small portions. This means that you can burn more calories in a day as the metabolism is boosted by eating for a shorter duration. So ditch the myth of eating less for longer to lose weight. Try to eat smart.
References
Blundell, J. E., Caudwell, P., Gibbons, C., Hopkins, M., Naslund, E., King, N., & Finlayson, G. (2012). Role of resting metabolic rate and energy expenditure in hunger and appetite control: a new formulation. Disease models & mechanisms, 5(5), 608–613. https://doi.org/10.1242/dmm.009837
Calculate basal metabolic rate (BMR) in adults (2021). https://www.gob.pe/14903-calcular-rate-of-metabolism-basal-tmb-en-adultos
Drotz, S. H., Sparrman, T., Nilsson, M. B., Schleucher, J., & Oquist, M. G. (2010). Both catabolic and anabolic heterotrophic microbial activity proceed in frozen soils. Proceedings of the National Academy of Sciences of the United States of America, 107(49), 21046–21051. https://doi.org/10.1073/pnas.1008885107
Luscombe, N. D., Noakes, M., & Clifton, P. M. (1999). Diets high and low in glycemic index versus high monounsaturated fat diets: effects on glucose and lipid metabolism in NIDDM. European journal of clinical nutrition, 53(6), 473–478. https://doi.org/10.1038/sj.ejcn.1600779
Pontzer, H., Brown, M. H., Raichlen, D. A., Dunsworth, H., Hare, B., Walker, K., et.al. (2016). Metabolic acceleration and the evolution of human brain size and life history. Nature, 533(7603), 390–392. https://doi.org/10.1038/nature17654
Vrieze, A., Holleman, F., Zoetendal, EG, de Vos, WM, Hoekstra, JB, & Nieuwdorp, M. (2010). The environment within: how gut microbiota may influence metabolism and body composition. Diabetology, 53(4), 606–613. https://doi.org/10.1007/s00125-010-1662-7
