How to boost your metabolism?
You have undoubtedly heard of metabolism and probably even know roughly what it is.
But.
There are many myths about the impact of metabolism on our health, especially, when it comes to weight loss.
So.
Let’s start from the very beginning.
What is metabolism?
Metabolism (from Greek: μεταβολή – change) is the set of chemical reactions that take place in the body to sustain life.
These reactions require energy so metabolism can also be defined as the set of chemical reactions that convert food into the energy needed to sustain life.
The main metabolic functions are:
1. Energy production or catabolism, or in simple words, the conversion of food into energy accessible to the body’s cells – carbohydrates, fats and proteins are broken down into glucose, fatty acids and amino acids and then converted into adenosine triphosphate (ATP), which our body uses to produce and store energy at the cellular level.
The main processes are glycolysis, the citric acid cycle (Krebs cycle) and oxidative phosphorylation.
2. Biosynthesis or anabolism, which provides the ‘building blocks’ and energy for synthesising complex molecules.
The main processes are protein synthesis from amino acids, nucleic acid synthesis from nucleotides, lipid synthesis from fatty acids and glycerol, and carbohydrate synthesis from simple sugars.
3. Detoxification and elimination of waste (metabolic by-products), which involves the conversion of toxic substances into less harmful substances and their elimination from the body. The liver plays a key role in detoxifying harmful compounds, while the kidneys filter waste products for excretion.
4. Nutrient recycling – the body processes nutrients from food into forms that can be absorbed and used by the body (digestion, absorption and transport of nutrients, including conversion of excess glucose into glycogen for storage in the liver and muscles).
5. Homeostasis or regulation – helps to maintain a stable internal environment in the body by providing optimal conditions for cellular function (regulating blood glucose levels and hormone production, maintaining acid-alkaline balance, etc.).
6. Cell maintenance and repair – provides the necessary components for cell maintenance, growth and repair (repairing DNA defects, synthesising new cell membranes and building cell structures, etc.).
7. Thermogenesis, or the production of heat to maintain body temperature (includes basal metabolic rate (BMR), which promotes heat production, and adaptive thermogenesis, which occurs in response to changes in environmental temperature or nutrition).
Simply put, metabolism is the internal process by which our body uses energy (burns calories) to convert ingested food and nutrients into energy for breathing, blood circulation, cell growth and repair, and whatever else is necessary for survival.
Thousands of different metabolic reactions are going on 24/7 in our bodies, and all these processes are strictly regulated and interconnected to ensure that the body’s needs are met efficiently.
Fast and slow metabolism
Fast metabolism usually refers to a faster Basal Metabolic Rate (BMR) – the amount of energy needed to maintain the body’s basic physiological functions at rest, within 24 hours.
People with a fast metabolism | People with a slow metabolism |
Burn more calories even at rest, e.g. when sleeping. | Burn fewer calories at rest, so they find it easier to gain (or harder to lose) weight. |
Converts food into energy faster/more efficiently. | Store calories as fat more quickly/efficiently. |
Maintains or reduces body weight more easily. | Calorie intake needs more attention to maintain a healthy weight. |
Feel more energetic and alert throughout the day. | Experience more frequent fatigue and lack of energy. |
Heart rate may be slower than normal (bradycardia). | Feel colder more often, even in warm environments, due to reduced heat release. |
| More likely to have skin and hair problems (dry skin, brittle hair etc.). |
| Experience sadness or depression more often, which may be related to hormonal imbalances. |
| More likely to experience brain fog or difficulty concentrating. |
Metabolic rate is affected by several factors, including:
- Body composition – muscle tissue burns more calories than fat tissue, so people with more muscle mass have a higher BMR.
- Age – metabolism tends to slow down with age, mainly due to loss of muscle mass and hormonal changes.
- Genetics – metabolic rate is also largely determined by heredity (body type).
- Hormonal factors – hormones (e.g. thyroid hormones) play an important role in regulating metabolism.
- Physical activity – regular exercise can boost metabolism by increasing muscle mass and calorie expenditure.
- Nutrition – The thermic effect of food (TEF), or the energy expenditure needed to digest, absorb and metabolise nutrients from food. Protein has a higher TEF than fat and carbohydrates, i.e. to process protein-rich foods, our bodies burn more calories.
Why boost your metabolism?
Speeding up your metabolism is often desirable for a variety of reasons, here are the main ones:
1. Weight control.
A faster metabolism means the body burns more calories at rest and during activity, making it easier to maintain a healthy weight or lose excess weight.
2. Higher energy levels.
A faster metabolism can lead to better use of nutrients for energy production leading to improved energy levels throughout the day.
3. Better physical performance.
Faster metabolism increases endurance and strength during physical activity, thus improving athletic performance.
And.
Promotes faster recovery after exercise by supplying nutrients to muscles and tissues more quickly.
4. Health benefits.
Faster metabolism helps regulate blood sugar levels, reducing the risk of insulin resistance and type 2 diabetes.
And.
Boosts lipid metabolism, potentially reducing LDL (bad) cholesterol and improving cardiovascular health.
5. Mood and mental clarity.
Stable blood sugar levels and sufficient energy from a well-functioning metabolism can positively affect mood, attention and cognitive function.
How can you boost your metabolism?
Boosting the metabolism means increasing the body’s total energy expenditure (total number of calories burned during the day).
To give you a general idea of how much energy our different organs and tissues use, below are the main energy consumers at rest.
| Number of calories burned per day | Percent of BMR |
Brain | ~240-320 kcal/day | ~20% |
Liver | ~320-440 kcal/day | ~20% |
Muscle (in people with muscle mass ~30-40 kg) | ~240-480 kcal/day | ~20-30% |
Heart | ~112-128 kcal/day | ~7-8% |
Kidney | ~80-112 kcal/day | ~5-7% |
Adipose tissue (in people with medium body fat) | ~40-80 kcal/day | ~5-10% |
Total daily energy expenditure (TDEE), which is on average ~2200-2500 kcal/day for men and ~1600-2000 kcal/day for women consists of:
- Basal metabolic rate ~ 60-75% (the amount of energy consumed at rest in a neutrally moderate environment, post-absorptive state, when the digestive system is inactive – after about 12 hours of fasting).
- Physical activity level ~15-30% (energy spent in different physical activities).
- Thermal effect of food ~10% (energy required for digestion, absorption and metabolism of food).
- Non-Exercise Activity Thermogenesis (NEAT).
As you can see, the biggest energy consumers in our bodies are the brain and the liver, whose energy consumption we cannot significantly increase.
But.
We can increase muscle mass, which is the third biggest energy consumer.
Men have 32.4 ± 3.7 kg of muscle, while women have 21.5 ± 3.2 kg on average.
1 kg of muscle at rest burns about 10-15 kcal per day, i.e. a man’s muscle at rest burns about 320 to 542 kcal per day and a woman’s muscle at rest burns about 210 to 370 kcal per day.
370 kcal per day is not much – that’s about the energy (calories) in 3 medium-sized bananas.
But.
When you start moving, the energy consumption of your muscles increases significantly:
- During moderate exercise, a person who weighs 70 kg can burn about 300-400 kcal per hour (e.g. walking at a moderate pace).
- During intense exercise, the same person can burn 500-800 kcal per hour (e.g. running or strength training).
How does muscle mass improve our metabolism?
1. Maintaining muscle requires 3 to 4 times more energy than maintaining fat tissue. This means that even at rest, muscle burns 3 to 4 times more calories than fat;
2. Muscle activity generates heat (thermogenesis). This process occurs not only during exercise but also during non-exercise activities and at rest. In other words, greater muscle mass increases the body’s ability to generate heat and burn calories, thus increasing total energy expenditure.
3. Glucose uptake occurs mainly in muscle tissue. More muscle mass increases the glucose uptake into muscle cells from the bloodstream, thus lowering blood sugar levels and improving insulin sensitivity. Better insulin sensitivity helps prevent and control type 2 diabetes and may contribute to more efficient energy use and storage.
4. People with a larger muscle mass can perform more intense and prolonged physical activities and use energy more efficiently during exercise. More exercise increases total energy expenditure during and after exercise (EPOC).
5. Strength training and muscle growth stimulate the release of anabolic hormones such as growth hormone and testosterone, which promote muscle growth and recovery leading to a faster metabolism.
6. An increase in muscle mass can contribute to a decrease in fat mass by burning more calories and improving metabolism. In turn, lower fat mass reduces the risk of metabolic diseases and improves the overall metabolic efficiency of the body.
7. Muscle cells have high numbers of mitochondria (the source of cellular energy). Increased muscle mass can increase mitochondrial density and function (in both muscle and brain), leading to more efficient energy production.
How to boost your metabolism?
Yes, it is possible to boost the metabolism and this can be done by changing your lifestyle and dietary habits:
1. Increase muscle mass.
Regular strength training such as weight lifting or high-intensity interval training (HIIT) can help increase muscle mass thus increasing the basal metabolic rate (BMR).
2. Become physically active.
Engage in regular physical activity such as walking, running, cycling and swimming (aerobic exercise) to increase calorie expenditure both during and after exercise (EPOC). Non-exercise thermogenesis (walking during breaks, climbing the stairs to the apartment, cleaning the house, mowing the lawn, etc.) can also contribute significantly to daily calorie burning.
3. Eat more protein.
Protein takes more energy to digest, absorb and process than fat and carbohydrates, so eating protein-rich foods can speed up your metabolism for a few hours (by increasing the thermic effect of the food).
And.
Small but frequent meals keep the metabolism active and prevent large fluctuations in blood sugar. You can read about how skipping meals affects our bodies HERE.
4. Drink enough water!
Water keeps all the substances in our body moving – if there’s not enough, something happens more slowly.
Drinking cold/cool water can directly contribute to calorie burning as the body uses energy to heat it to body temperature.
Read more about how much water you should drink and why HERE.
5. Get enough sleep.
Poor night’s sleep can upset the balance of hormones like insulin and cortisol that regulate metabolism. 7-9 hours of quality sleep can help maintain a healthy metabolic rate.
Read more about how much deep, shallow and REM sleep we need HERE.
6. Try to reduce stress.
Chronic stress can cause hormonal imbalances, such as elevated cortisol levels, which can slow metabolism.
Read more about how stress affects our body and mind HERE.
7. Use spices.
Spicy foods, especially those containing capsaicin (found in chilli peppers), can temporarily speed up metabolism by raising body temperature and energy expenditure. Read more about spices and herbs HERE.
Key takeaways
A faster metabolism can help you lose weight and keep it off while providing you with more energy.
And.
All it takes is a small change in your lifestyle and eating habits.
However.
As usual – it’s not that simple, because changing lifestyle and eating habits is hard (for example – only ~20% of people who lose weight manage to keep it off in the long term).
This is mainly because if doing everything yourself:
1. You lack knowledge:
- People may not understand the balance of required macronutrients (protein, fat, carbohydrates) or the importance of micronutrients.
- Incorrect exercise selection and/or execution and a lack of understanding of progressive overload can lead to poor performance or injury.
2. Unrealistic goals are set.
People genuinely believe that they can transform their bodies or reduce the weight they have gained over many years in a matter of weeks, and, when this does not happen, instead of adjusting their goals, they look for other training plans or miracle drugs or settle and do not try to make any more changes in their lifestyle and dietary habits.
3. Insufficient motivation.
Relying on external factors (e.g. public recognition) rather than intrinsic motivation (personal health and well-being) is usually unsustainable.
4. Emotional and psychological factors.
Stress and emotional problems can lead to unhealthy eating habits and interfere with consistent adherence to diet and/or fitness plans.
5. Lack of a personalised approach.
Popular diets and generic exercise plans may not meet the specific needs, preferences and body type of a particular individual.
In other words, you always have a choice:
- Do everything yourself.
Or.
- Consult a professional – dietician, nutritionist or trainer – to do everything more efficiently and reach your goals faster.
Eat delicious, eat balanced and – be healthy!
Biochemistry [5th Revised edition]
The detoxification enzyme systems
Biochemical and Physiological Aspects of Human Nutrition
Brown adipose tissue: function and physiological significance
Adaptive thermogenesis with weight loss in humans
Metabolic effects of obesity: A review
Basal metabolic rate as an integral indicator of metabolism intensity
Sugar for the brain: the role of glucose in physiological and pathological brain function
Isotope tracers in metabolic research: principles and practice of kinetic analysis
Skeletal muscle metabolism is a major determinant of resting energy expenditure
Molecular Mechanisms of Renal Ammonia Transport
Adipocytes as regulators of energy balance and glucose homeostasis
Skeletal muscle metabolism is a major determinant of resting energy expenditure
Exercise and type 2 diabetes: molecular mechanisms regulating glucose uptake in skeletal muscle
Exercise Training Increases Mitochondrial Biogenesis in the Brain
Exercise-induced increase in muscle insulin sensitivity
Changes in Energy Expenditure Resulting from Altered Body Weight
Dietary Protein and Muscle Mass: Translating Science to Application and Health Benefit
Sleep deprivation and obesity in adults: a brief narrative review
Four nights of sleep restriction suppress the postprandial lipemic response and decrease satiety
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