What does metabolism mean to you? Most people associate the word metabolism with weight management, exercise, or how much food we can eat! However, metabolism is a lot more than just the process of breaking down fats or burning extra calories.
Every cell in our body is constantly working to produce the substances and energy needed to sustain life, and metabolism is a process that’s essential for the continuity of these processes .
Despite its fundamental importance to our health and functioning, there’s quite a lot of ambiguity around the concept of metabolism - especially what it means when ours slows down and what we can do about that. While all of it is worthy of a deep dive, we’ve tried to simplify it for you here.
What is metabolism?
Every second, there are several chemical reactions constantly take place inside our body (or any organism’s body) to keep us alive.
Metabolism can be defined as the sum total of all these processes, which, together, allow all organisms to stay healthy, while building and maintaining the physical structures we need .
Let’s look at how it helps us with each of these, starting with how it helps us stay healthy.
How metabolism helps us stay healthy:
- Converts food into energy, for our cells to function properly
- Converts food into the building blocks of our body like protein, nucleic acids, etc., and,
- Eliminates waste and toxins
How metabolism helps us build and maintain our physical structures:
Our metabolism follows two types of processes: anabolism and catabolism .
- Anabolism is when smaller molecules combine to make up a larger one. For example, amino acids (the building block of protein) combine to make collagen, a protein that’s a major part of our body’s tissues.
- Catabolism, on the other hand, is when complex molecules are broken down into simpler, smaller molecules. For example, the sugar we eat breaks down into glucose, which is a form our body can use either for energy, or to create other structures through anabolism.
Simply put, anabolism is the building-up of molecules, with the help of the simpler molecules created through catabolism. Both these reactions occur simultaneously and continuously to keep us alive.
A healthy metabolism drives all of these functions - and our metabolic rate is, in turn, what determines a healthy metabolism.
What is our metabolic rate and why does it matter?
Our metabolic rate is the rate at which our body uses energy to function properly - in other words, it’s the amount of energy we use every day .
This is majorly a combination of our:
- Basal metabolic rate (BMR): this is the minimum energy required by our body to develop and maintain our organs while our body is at rest . This contributes to a whole 60-75% of the energy we use every day !
- The thermic effect of food (TEF): the amount of energy used to chew, digest and store nutrients from our food is called the thermic effect of food or TEF . This approximately contributes to 10% of the energy we use every day .
- Energy used during physical activity: Exactly what it sounds like! What’s interesting about this is that “activity” here includes anything - from planned exercise like running or playing an outdoor sport, to incidental things like hanging washed clothes or even fidgeting; it can constitute anywhere between 15 to 30% of the energy we use every day .
When our metabolic rate slows down, that means our body’s ability to use energy also reduces. When this happens, any energy that isn’t being used for metabolic purposes then gets redirected to our body’s fat stores, to allow it to be used in the future [10, 11, 12].
Naturally, this isn’t an ideal situation, since this leads to an accumulation of fat in the body. Let’s have a look at what affects our metabolic rate and how we can increase it.
Controlling our metabolism
Not all of the factors that determine our metabolism are in our control. Our age, gender and our genetic makeup are some examples. For instance, men tend to have greater muscle mass, which means a higher BMR than women [13, 14, 15].
That said, there are 2 things that we can actively do to improve our metabolism:
1. Building more muscle
Our metabolism is directly proportional to our muscle mass .
That's because our muscles are metabolically more active, which means people with lean, muscular bodies expend more energy every day, as compared to people with a higher percentage of body fat .
2. Managing our stress
Another lifestyle-related factor that has a tremendous impact on our metabolism: our stress levels.
People who have higher levels of cortisol (a hormone secreted by our body when it’s under stress) tend to be overweight. That’s because elevated levels of cortisol are associated with an increased appetite .
In fact, a study also associated being more stressed with a slower metabolism, and a lower rate of fat breakdown. This makes us more likely to store extra fat, and increases our risk of obesity . We can manage our stress and cortisol levels through stress-relieving activities such as meditation and yoga. .
In short: the answer to controlling our metabolic rate lies in following a healthy lifestyle, where we stay physically active, maintain a balanced diet (with plenty of protein) and find ways to de-stress and manage our cortisol levels.
We hope this article helped you understand what metabolism really means. Leave a comment below if you still have any questions about metabolism. :)