Metabolism Explained: What It Does And How It Works

In this article:

• Metabolism is the collection of processes your body uses to turn food into energy and support essential functions.
• Your metabolic rate can vary depending on factors such as age, muscle mass, activity levels, hormones, sleep and genetics.
• Metabolism can change as you age, with muscle mass and physical activity both playing a role.
• Everyday habits like regular movement, nourishing meals, sleep, and recovery can help support healthy metabolic function.

Metabolism is a process that’s happening in your body all the time. Whether you’re moving, eating, or sleeping, your metabolism is at work. 

While metabolism is often associated with weight and calorie burning1, it does much more. Metabolism plays an important role in keeping your body functioning day to day, providing the energy needed for everything from digestion to movement and repair. 

In this article, we look closer at what metabolism means, how it works, and the different factors that can influence it. 

What is metabolism?

Metabolism refers to the chemical processes your body uses to convert food into energy, support growth and repair, and maintain essential body functions². Your body breaks food down into components it can use, helping provide a steady supply of energy to cells throughout your body². 

Metabolism also includes processes involved in cell growth and development³, as well as providing the energy and building blocks your cells need for everyday repair⁴ ⁵. 

You may have heard of a fast metabolism or a slow metabolism. These terms generally refer to differences in how quickly your body uses energy. Metabolic rate varies from person to person, with different factors influencing it. 

What does metabolism do?

Your metabolism is involved in many of the processes that keep your body functioning every day. These include:

• Energy production: converting nutrients into energy that can be used by your cells¹.
• Muscle and organ function: providing energy to help your muscles and organs carry out their everyday roles⁶.
• Brain activity: helping provide the steady supply of energy your brain needs to function⁷.
• Cellular repair: supporting the processes involved in maintaining and repairing cells⁴.
• Temperature regulation: contributing to the way your body maintains its internal temperature⁸.
• Hormone processes: supporting processes involved in producing and regulating hormones¹.

How does metabolism work

At a basic level, metabolism works in three stages9:

1. Food is broken down into nutrients. 
2. Those nutrients are converted into energy. 
3. Cells use that energy to carry out everyday functions, from muscle movement to brain activity9.

This energy is often measured in calories, a unit used to measure how much energy food provides and how much energy your body uses10. How much energy your body uses can vary from person to person, with factors such as age, body composition, and activity levels all playing a role. 

What affects metabolism

Your metabolic rate can be influenced by a range of factors¹¹. Some relate to your individual biology, while others are connected to your lifestyle and daily habits. These include: 

• Age: metabolic rate can change as you get older.
• Muscle mass: muscle requires energy to maintain, even while you’re resting.
• Physical activity: movement increases the amount of energy your body uses.
• Sleep and stress: both can influence processes involved in energy regulation.
• Hormones: hormones help regulate how your body uses and stores energy12.
• Nutrition: what and how much you eat can influence energy expenditure.
• Genetics: individual genetic differences can play a role in metabolic rate.

Together, these factors help explain what increases metabolism for one person compared to another, and why metabolic rate can vary so much between individuals.

Does your metabolism slow down as you age?

Metabolism can change as you get older, but age is only one part of the picture. Muscle mass tends to decrease over time and physical activity levels can also change, both of which may affect how much energy your body uses¹³.

Staying active and maintaining muscle mass can help support metabolic health as you age. Regular movement, strength-focused exercise and adequate protein intake can all play a role in maintaining muscle mass and supporting your body’s energy needs¹³.

How to improve your metabolism

There’s no single habit or quick fix that will transform your metabolism. Instead, supporting healthy metabolic function comes down to looking after your body consistently through everyday habits such as: 

• Eating regular, nourishing meals
• Prioritising sleep and recovery
• Staying hydrated
• Building strength and staying active
• Managing stress where you can
• Supporting muscle health through movement and nutrition¹⁴ ¹⁵

Metabolism is a complex process, and it naturally varies from person to person16 . Your energy needs can also shift across various stages of life, which is completely normal17.

While you may hear about different ways to boost metabolism, sustainable habits are a more realistic way to support your metabolism and overall health over time18. 

Supporting your metabolism through everyday habits 

Your metabolism is working around the clock to help provide the energy your body needs. While there’s no single trick to changing how it works, understanding the factors that influence it can help you make more informed choices about your everyday health.

From staying active and eating well to getting enough sleep and looking after your overall wellbeing, supporting your metabolism is less about quick fixes and more about habits you can maintain over time.

To discover more about health and wellbeing, check out the Swisse Wellness Hub. Explore more articles like the science behind gut health and a guide to vitamins for energy online. 

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