Posted on September 14, 2022 by Kate Halsall

Metabolism is the technical term for the process by which your body converts food into energy. However, this seemingly innocuous process is the root of much frustration, anger and resentment in the fitness world. People who struggle with losing weight will complain of too slow a metabolism and the frustration of gaining weight by even looking at food, while people who struggle to gain weight will be infuriated that despite eating as much as they can stomach they seem unable to gain a pound. What is going on here? Why is it that people seem to have such starkly different metabolisms and what can be done to achieve your fitness goals in the context of your metabolism? When it comes to metabolisms, what is fact and what is fiction?

How do metabolisms work?

As previously mentioned, your metabolism is the fire of the furnace where fuel you’ve consumed is thrown, providing energy for your body to perform all of its different functions. However, there are different parts that comprise your total metabolism. Firstly, your BMR or Basal Metabolic Rate. This refers to the amount of energy required to simply keep you alive, performing essential functions like breathing, circulation, hormone production and the growth and repair of cells. This constitutes the majority of the total energy you expend each day. Second is your food processing or thermogenesis. The physical process of ingesting, digesting, storing and excreting food requires energy itself, accounting for approximately 6% to 10% of daily energy expenditure. Finally you have the physical activity you perform each day, which includes non-exercise activity (NEAT) such as walking around, opening doors or fidgeting as well as all your daily exercise. Physical activity usually accounts for between 20% to 40% of daily energy expenditure and is the easiest metabolic variable to directly influence. For some fresh ideas to help you keep your metabolism high, have a look at the link here. Your total metabolism, and each of the aforementioned factors, is influenced by a wide array of variables, some within our control and others very much beyond it. So what are these variables and how do they contribute to people having such wildly different metabolisms?

Why do people have different metabolisms?

The first of these many factors is sex. Men tend to be larger and carry proportionately more muscle mass and less body fat, meaning they tend to have a higher BMR than women, as their larger, heavier bodies require more energy to maintain. Second is age. As we get older we tend to lose muscle mass and gain body fat. There is some debate as to whether this is because the metabolic process itself begins to slow or if lifestyle changes caused by aging contribute to this degeneration. However, in any case, these physiological changes cause the metabolism of older people to be slower than that of younger people.

Third is somatotype. Somatotype refers to what type of frame you have. Ectomorphs are people who are naturally slim, lightly muscled, with narrow shoulders and slim waists. They typically have difficulty gaining weight and are naturally suited to endurance sports. Mesomorphs are people who are naturally lean and muscular with broad shoulders and narrow waists. They have a good strength to weight ratio and are strong all-round athletes. Finally, endomorphs are people with a natural propensity towards fat storage and weight gain. They are muscular despite having higher body fat percentages and as such are naturally suited to heavy throwing events and weightlifting. These archetypes are not absolute, rather they are a sliding scale, with many people falling somewhere between ectomorph and mesomorph or mesomorph and endomorph.

The final factor is hormones. Hormone profiles can vary widely across different people and are specific to the individual. Your thyroid function plays a particularly major role, releasing hormones responsible for the synthesis of macronutrients. This then determines how quickly your body processes different foods, which in turn dictates how fast or slow your metabolism is. Thyroid conditions that cause people to uncontrollably gain or lose weight are pretty rare, however thyroid function is definitely a significant factor in the overall process. So with all this said, how should someone use this information to help them achieve their fitness goals?

How do I best manage my metabolism?

The first thing you can do to manage your metabolism is to make sure you are regularly exercising. There are very few things in life for which this can be said, but regular exercise is an unparalleled positive for everyone universally. No matter what your goals are, making sure that you are consistently in the gym performing some forms of strength training and cardio will absolutely serve you well. If you struggle to gain weight, regular strength training will help you create the stress needed to promote muscle gain, while if you struggle with weight loss regular cardio training will help increase your daily energy expenditure, meaning you can consume more each day without gaining additional weight.

The second thing you can do is review your core attributes to understand what your body needs. What sex are you? How old are you? What somatotype are you? Do you have any hormonal conditions or imbalances? Addressing these individual factors will be key to managing your metabolism and will benefit you in your fitness journey more generally. After all, it is YOUR fitness journey, not anyone else’s, so its really important that you understand yourself and your needs. If you’re still unsure an example could be that if you were a female, 40 year old, endomorph with normal hormones for your age, you will likely have a slower metabolism and higher body fat percentage, and so may benefit from more cardio training accompanied by a lower calorie diet. For some more guidance on how to manage your metabolism, check out the links here and here!

The third thing you can do is ask for help. Often people stress themselves out when they don’t immediately get results and will become frustrated with themselves for being unable to deal with the insanely complicated factors that contribute to how your body works. Reach out to personal trainers, nutritionists and other experts who can alleviate this stress for you and help guide you on your fitness journey. There will still be ups and downs, with trial and error still being a fundamental part of the process. However, using the skills, knowledge and experience of other people to help you is one of the best ways to get the most out of your training.


In conclusion, metabolism is the process of burning the fuel you provide to the body. This is driven by our basic bodily functions, digestion and our day-to-day activity. People have faster or slower metabolisms depending on their sex, age, somatotype and hormones. While most of these factors cannot be directly changed, they can be accounted for and addressed by your approach to exercise and nutrition. However, as this can be extremely difficult and stressful, it is a good idea to seek out experts and professionals who can help you. Motive8 north is one such place where we are 100% dedicated to helping you achieve your goals and we have the skills and knowledge to back that desire up. Come down to Marshall’s Court to start your fitness journey in earnest today!