Metabolism is a common topic of conversation. Some will talk about having a slow or a fast metabolism. But, what exactly does this mean and can we change it? Read on to find out.
What Is Metabolism?
In essence, metabolism is a range of biochemical processes that occur continuously within a living organism to keep it alive and its organs functioning. It involves the building and breakdown of substances. The term metabolism is often used to refer to the breakdown of food and it’s conversion into energy. 1
What Impacts Our Metabolism?
Each of us has a basal metabolic rate. We burn energy at rest in order to keep our bodies functioning and to keep vital functions going, including breathing and keeping warm. The energy required for these functions is known as our Basal Metabolic Rate or BMR. BMR accounts for around 60-70% of our body’s total daily energy requirements. (2) Our BMR is affected by different factors such as hormones, gender, age, stress, genetics, height, weight and muscle mass.
Our day-to-day activities and exercise levels impact how much energy we burn in addition to our BMR. Our physical activity level is often referred to as our PAL. The more active we are, the more energy we burn.
Can We Change Our Metabolism?
As mentioned, there are different factors that influence our BMR. For example, someone with a higher muscle mass will require more energy to maintain their body mass than somebody of the same weight but with a lower muscle mass. Muscle is a highly metabolically active tissue and uses up more energy when at rest than fat.
Men have a higher metabolism than women, due to having higher levels of muscle mass. This is why the average man requires 2500 calories to maintain his weight whereas a woman requires 2000 calories per day.
Age also affects our metabolism or the amount of energy we require. As we age we lose muscle and our bodies simply require less energy which therefore alters our metabolic rate.
How Are Metabolism And Weight Loss Related?
When we gain weight or struggle to lose weight, this is often blamed on having a “slow metabolism”. A “slow metabolism” would more accurately be described as a lower BMR. As discussed above, our metabolic rate is based on several factors, some of which we can control and others we cannot. For example, we can’t make ourselves any younger but we can reduce fat mass and increase muscle mass which can help to improve our metabolic rate. Being physically active will also increase our metabolism as your body requires energy for the additional activity.
Anybody has the capability to lose weight, even for those who feel they have a slow metabolism. Achieving a calorie deficit is a good place to start. This is when the calories we consume, through food and drink, are lower than the calories we burn (including our BMR and our physical activity level.)
So What Can We Do?
Staying active is key. The NHS (3) recommends to:
- Be physically active every day
- Do at least 150 minutes of moderate intensity activity or 75 minutes of vigorous activity each week
- Reduce time spent sitting
- Do strengthening exercises or resistance training twice per week
In addition to this we need to consider out dietary choices:
- Ensure you consume at least 5 portions of fruit and vegetables per day; not only are they full of nutrients and fibre, but are low in calories
- Regulate your portion size
- Listen to your hunger and fullness cues and let this guide when you eat and when you don’t need further food
- Include some healthy fats, e.g. nuts, olive oil, but don’t consume in excess due to the high levels of calories
- Be aware of cooking methods, choosing ones that don’t require additional fats or calories
- Maintain adequate protein intake; this can help to prevent the loss of lean mass and can help to manage hunger and satiety.
- Vybornaya KV, Sokolov AI, Kobelkova IV, Lavrinenko SV, Klochkova SV, Nikityuk DB. [Basal metabolic rate as an integral indicator of metabolism intensity]. Vopr Pitan. 2017;86(5):5-10. Russian. doi: 10.24411/0042-8833-2017-00069. Epub 2017 Sep 8. PMID: 30695621.
- Weekes, E. (2020). Nutritional requirements in clinical practice. https://www.bda.uk.com/uploads/assets/e26c7e5e-6825-4bb9-96e772609f59c4c2/Manual-of-Dietetic-Practice-Chapter-61-Nutritional-requirements-in-clinical-practice.pdf.
- NHS (2019). Exercise. https://www.nhs.uk/live-well/exercise/