What is metabolism?
Metabolism is a term which refers to all the ongoing biochemical processes essential for your body to stay alive. These include the consumption of nutrients, such as protein, fats or carbohydrates, which are processed into the energy required by cells.
Metabolism is also referred to as the metabolic rate. It denotes the rate of the metabolic reactions occurring in the body (e.g. basal metabolic rate, total metabolic rate, etc.) and is linked with the caloric demand. There are many factors which determine your caloric requirements, such as your age, sex, body weight, amount of muscle tissue and level of physical activity. These are the same factors you can use to modulate your metabolism and influence its condition.
FACT: Metabolism is not the same as digestion
During my career as a nutritionist and trainer I have repeatedly heard people judge someone’s metabolic rate on the basis of... the frequency and number of their bowel movements. How many times and how often you go to the toilet is only indicative of the rate of your digestion, but has nothing to do with your metabolism. By definition, metabolism covers all the chemical reactions and energy transformation processes taking place in the body and the link between metabolism and digestion is not related to the pace of gastrointestinal transit. Digestion is a process that requires energy, i.e. a specific number of calories that need to be burned for the digestive processes to take place at all – and that is the only connection between digestion and metabolism.
Check also: “6 Effective Exercises for Better Digestion”.
MYTH: Catabolism is bad
Metabolic processes can be divided into anabolic (building) and catabolic (breakdown) ones. The importance of the former is especially strongly emphasized in the world of sports. After all, building and strengthening muscle tissue mostly involves anabolic processes. This reasoning leads many people to try to avoid catabolism, because it might be associated with muscle tissue loss. However, catabolism, just like anabolism, is a natural process your body needs to function properly. Catabolism does not only lead to muscle loss, but also promotes the burning of fat tissue and the digestion of nutrients. There should be a balance between catabolism and anabolism, like in all biochemical processes.
MYTH: Drinking warm water with lemon on an empty stomach boosts your metabolism
The habit of drinking a glass of water first thing in the morning has a very positive effect on health, as it ensures that the body is properly hydrated. However, just by adding some lemon, mint or ginger you will not turn the water into a magic concoction enhancing the rate of your metabolism. You should drink plenty of water (with or without additions) at any time of day, but this does not mean that you will lose weight faster or that you will burn more calories.
Read also: “4 recipes for isotonic drinks that hydrate better than water”.
FACT: In most people, metabolism slows down with age
Although recent scientific studies show that the metabolic rate does not physiologically slow down until around the age of 60, in practice most people experience this effect earlier. This is not due to the aging process itself, but rather has to do with changes to people’s lifestyle which reduce their muscle mass. As we age, we tend to exercise less, so we lose muscle mass, which is an essential factor determining the rate of metabolic processes. This does not only mean we stop practicing sports or working out, but we also walk less or avoid climbing stairs.
MYTH: You cannot change your metabolic rate
Quite the contrary, you can influence your metabolic rate both directly (e.g. by doing more exercise) and indirectly – by leading a generally healthy lifestyle and keeping your organs (e.g. the thyroid) in a good condition. However you look at it, you can do plenty to tweak your metabolic rate and which way it will ultimately go depends on your daily choices – even the smallest of them.
FACT: Coffee and green tea enhance metabolism
Coffee and green tea do enhance metabolism. It is all thanks to their caffeine content. It speeds up the metabolic rate, while at the same time facilitating your weight reduction journey. Remember, however, that drinking coffee or green tea will not in itself overhaul your metabolism, as it is mainly affected by your general lifestyle, including physical activity, while caffeine-containing beverages can only serve as an additional booster.
NOTE: In the case of caffeine, more does not equal better – the maximum daily dose recommended for adults is 400 mg, i.e. ca. 4-5 cups of coffee (a single espresso shot contains ca. 80 mg of caffeine).
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Sources:
1. Tabrizi R, Saneei P, Lankarani KB, Akbari M, Kolahdooz F, Esmaillzadeh A, et al. The effects of caffeine intake on weight loss: a systematic review and dos-response meta-analysis of randomized controlled trials. Critical reviews in food science and nutrition. 2019.
2. Steffl M., Bohannon R.W., Sontakova L., Tufano J.L., Shiells K., Holmerova I., Relationship between sarcopenia and physical activity in older people: a systematic review and meta-analysis, „Clinical Interventions in Aging”. 2017.
3. Pontzer H., Yamada Y., Sagayama H., Ainslie P., Andersen L., Anderson L., Arab L., Baddou I., Bedu-Addo K., Blaak E. i wsp., Daily energy expenditure through the human life course, „Science”. 2021.
4. https://zpe.gov.pl/a/metabolizm/D1DvmMgiw.