18 minutes

Metabolism Ultimate Guide | What Does Your Metabolism Do?

What is Metabolism? 

Metabolism is a process that takes place in your body. It is the way your body cells convert the food you eat to the energy you use to pretty much do everything as a human. 

Breathing, moving, thinking, talking…everything you do. Metabolism keeps you alive. 

So even while you are sleeping, or you are just lying quietly on a couch, your body is as active as ever. As opposed to some beliefs, your body does not “shut down”. 

This is because it is always consuming and storing energy from the food you eat while also breaking down and building up the molecules required to keep your health in good shape.

Aside from the food you eat there are organs and glands in your body that are responsible for the regulation of your metabolism. Let us briefly explore the processes  responsible for metabolism.

What Does Your Metabolism Do?

Metabolism is like your body's engine. It's a bunch of chemical reactions that turn the food you eat into energy and the building blocks your body needs to stay alive and do things like move, think, and grow.

It does a few important things:

  • Turns Food into Energy: It breaks down the food you eat (carbs, proteins, fats) into energy your body can use.
  • Builds and Fixes Stuff: Metabolism helps your body make and repair things like muscles and other body tissues.
  • Gets Rid of Waste: It also gets rid of waste that your body doesn't need.

Your metabolism speed can be influenced by things like your age, genetics, how much muscle you have, and how active you are.

What are The Types of Metabolism?

There are two primary types of metabolism:

Catabolism: This is the breaking down of larger molecules into smaller ones, releasing energy. For example, when you digest food, it gets broken down into simpler substances like sugars, which release energy for your body to use.

Anabolism: This is the building up of complex molecules from simpler ones, using energy. For instance, when your body creates proteins from smaller units called amino acids or stores energy by creating fat molecules from smaller components, it's anabolic.

So, catabolism breaks things down to release energy, while anabolism builds things up using energy. Both processes work together to maintain the body's functions and structure.

How Does Metabolism Affect Weight?

Metabolism plays a crucial role in influencing weight by determining the rate at which your body converts food into energy. It's the process by which your body converts the food and drink you consume into energy that is used to power various bodily functions.

Here's how metabolism affects weight:

  • Calorie Burning: Metabolism determines how fast your body burns calories for energy.
  • Basal Metabolic Rate (BMR): This is the energy your body uses at rest to keep you alive and functioning. People with higher BMRs burn more calories, even when not doing anything.
  • Physical Activity: Metabolism affects how many calories you burn during exercise and daily activities.
  • Muscle vs. Fat: Having more muscle helps burn more calories, as muscle burns more than fat, even when you're not moving.
  • Age, Genes, and Hormones: Metabolism slows with age, and genetics and hormones also impact how fast or slow it runs.

While metabolism plays a crucial role in weight management, it's not the sole factor. Diet, physical activity, genetics, hormonal balance, and other lifestyle factors also significantly impact weight. Strategies to maintain a healthy weight often involve a combination of balanced eating habits, regular physical activity, and lifestyle modifications tailored to individual needs.

How Many Types of Metabolic Rates Are There? 

Metabolic rate refers to the rate at which an organism uses energy or burns calories. There are several types of metabolic rates, and the key ones are:

1. Basal Metabolic Rate (BMR): 

BMR is the amount of energy expended while at rest in a neutrally temperate environment, typically measured in a fasting state. It represents the energy required to maintain basic physiological functions such as breathing, circulation, cell production, and temperature regulation.

2. Resting Metabolic Rate (RMR): 

RMR is similar to BMR, but is measured under less strict conditions. It includes the energy needed for the body's basic functions while at rest but doesn't require fasting or a specific environment.

3. Thermic Effect of Food (TEF): 

TEF refers to the energy expended during digestion, absorption, and utilization of nutrients in food. Different macronutrients (carbohydrates, fats, proteins) have varying effects on TEF.

4. Total Daily Energy Expenditure (TDEE):

TDEE represents the total amount of calories a person burns in a day, taking into account physical activity, BMR, and the thermic effect of food (energy expended during digestion and absorption of food). TDEE is crucial for understanding energy balance and weight management.

5. Exercise Metabolic Rate (EMR):

EMR is the amount of energy expended during physical activity and exercise. It includes the calories burned during structured exercise routines, such as running, weightlifting, or other forms of physical activity.

What are the Factors Affecting the Metabolic Rate?

Several factors can influence an individual's metabolic rate, including:

  • Body Composition: Lean muscle mass requires more energy at rest than fat tissue. Thus, individuals with a higher proportion of muscle tend to have a higher metabolic rate.
  • Age: Metabolic rate tends to decrease with age. This decline is often associated with a decrease in muscle mass and a decrease in physical activity levels.
  • Gender: Generally, men tend to have a higher metabolic rate than women. This difference is often due to men having more muscle mass and typically being larger in size.
  • Genetics: Genetic factors can influence metabolic rate. Some people may inherently have a faster or slower metabolism due to their genetic makeup.
  • Hormones: Thyroid hormones play a crucial role in regulating metabolism. An imbalance in these hormones can affect metabolic rate. Other hormones, such as cortisol, insulin, and adrenaline also impact metabolism.
  • Physical Activity: Exercise and physical activity increase metabolic rate both during the activity and afterward. Regular physical activity can lead to an increase in muscle mass, which in turn boosts resting metabolic rate.
  • Diet: The thermic effect of food (TEF) is the energy required for digestion, absorption, and storage of nutrients. Different macronutrients have varying effects on TEF; for example, protein requires more energy to digest compared to fats or carbohydrates.
  • Environmental Factors: Temperature extremes, such as cold or hot environments can influence metabolic rate. The body uses more energy to regulate temperature in extreme conditions.
  • Stress and Illness: Stress and certain illnesses or medical conditions can affect hormone levels and, subsequently, metabolic rate. For instance, prolonged stress can elevate cortisol levels, which may impact metabolism.

Knowing about these things can help you make changes to your daily life that might make your metabolism work better. But remember, everyone's body is different, and metabolism is complicated, affected by many things that work together.

What Hormone Controls Metabolism? 

Aside from the food you eat, you might be curious as to what controls your metabolism and the organs responsible for metabolism. Inside our body as well, certain hormones are for your metabolism.

These hormones are often referred to as signal molecules. They are responsible for telling your body when to store and when to use energy, and also when to break up and build up some vital nutrients. Several hormones are produced in the body but there are certain of them that are responsible for your metabolism. These are:

Thyroid Hormones

The thyroid gland is located in front of your windpipe. It is only a few inches long, but the role it plays in your body’s metabolism outweighs its size by a ridiculously large extent. The thyroid gland secretes two vital hormones. namely T3 and T4.

The T3 and T4 hormones are transported via your bloodstream and they control your metabolism in several ways. They tell your body cells when nutrients are to either be broken down or built up. Another tiny gland known as the pituitary gland located in your brain is responsible for the production of these thyroid hormones.

Let’s put it into perspective. When the level of your thyroid hormones is too low, your body begins to store more fat than it requires,start to gain weight, and you might start feeling fatigued. You might also experience hair loss.

What happens if there are too many thyroid hormones in your bloodstream? You guessed right! 

In this case, your body starts breaking down fat rapidly. Your body needs fat but, when there is an irregularity in your thyroid hormone level, it can result in excess use of fat. It can also result in excess elimination of fat and eventually weight loss, accompanied by other undesirable effects like sleep irregularities and high blood pressure. 


Also known as the “stress hormone”, Cortisol is second on the list of hormones that are responsible for your metabolism. The hormone is released into your bloodstream immediately after your body perceives an emergency or when it feels threatened. The response it produces is that sugar molecules (glucose) are quickly pumped into your blood and this provides you with the energy you require to respond to the perceived danger.

In a chronic situation where you are under stress, say maybe you need to meet a deadline, cortisol still pumps glucose into your bloodstream but your body will not use this extra glucose, so it will instead convert the glucose into fat. This is why too much stress can result in excess cortisol and eventually weight gain.


This hormone is often thought of as the male sex hormone, but it also plays an important role in the control of your metabolism; even as a female. The hormone plays an important role in the production of muscles and the metabolism of fat. When they are present at lower levels, it prompts an increase in fat mass and if it is present in too much proportion, it can lead to a change in sperm count for men and excess weight gain and acne for women.

Is There a Way to Control Your Metabolism? 

Naturally, metabolism declines as you age and as you do not have control over your age, there are simple ways in which you can keep your metabolism in control. Here are a few of the most effective ones:

  • Do not skip meals (breakfast especially): It is not just termed “the most vital meal of the day” for no reason. Eating a proper breakfast will help set your body metabolism to start your day.
  • Keep fueling yourself with water: All of the processes and chemical reactions in your body need water, it also helps detoxify your body.
  • Workout: It is a good practice to strengthen your muscles; it makes you more efficient in burning calories.
  • Sleep: Get enough quality sleep.

What is Metabolic Age?

Metabolic age is a comparison of your body's calorie-burning efficiency to others in your age group. If your metabolic age is lower than your actual age, your body might be burning calories more efficiently. If it's higher, your body might be burning calories at a slower rate. It's a way to gauge how well your metabolism is functioning compared to what's typical for your age.

Why is Metabolic Age Important?

Metabolic age is a measurement that indicates the efficiency of your body's metabolism relative to your chronological age. It's not an actual age but rather a representation of how well your body is functioning in terms of metabolism, typically assessed through various factors like body composition, weight, muscle mass, and fat percentage.

Why it's important:

Health Check: It shows if your body is working efficiently. A younger metabolic age is good, while an older one might mean your body needs attention.

Fitness Guide: Helps plan exercise and diet. If your metabolic age is higher, you might need to focus more on healthy habits to improve it.

Motivation: Seeing improvements in your metabolic age can motivate you to stick to healthier habits.

Prevention: A higher metabolic age might indicate risks for health issues like obesity or diabetes, so it's a warning to take action early.

Personal Plans: Helps create personalized plans for weight, muscle, and overall health.

Remember, while metabolic age is useful, it's not the only thing that matters for wellness. Other factors like genes, lifestyle, and medical history are also important. Always consider it alongside other health information and consult with a healthcare provider for a full picture of your health.

How to Calculate Metabolic Age?

Metabolic age is a concept used to evaluate how efficiently your body's metabolism functions compared to others of the same age group. There isn't a direct formula to calculate metabolic age, but various factors are considered:

Body Composition: Measures like body fat percentage, muscle mass, and distribution of fat around the body affect metabolic age.

Basal Metabolic Rate (BMR): This is the number of calories your body needs to maintain basic functions at rest. Factors like age, weight, height, and gender are used to estimate BMR.

Physical Activity Level: Regular exercise and physical activity influence metabolism and can affect metabolic age.

While there's no standardized equation for metabolic age, health professionals often use specialized scales or algorithms that consider these factors to estimate metabolic age. Some scales use bioelectrical impedance analysis (BIA), which sends a low-level electrical current through the body to estimate body composition.

Remember, metabolic age isn't a definitive measure of health but rather an estimate based on various factors. It's important to focus on overall health through a balanced diet, regular exercise, and healthy lifestyle choices rather than fixating on a single number.

Can I Fix My Metabolic Age?

Improving your metabolic age often involves making lifestyle changes that positively impact your metabolism. Here are some tips that might help:

  • Keep moving: Get active with activities you enjoy, like dancing or hiking. Mix it up with cardio (running, cycling) and strength exercises (lifting weights) to feel stronger and boost your metabolism.
  • Eat fresh: Focus on whole foods, veggies, lean proteins, and complex carbs. Avoid processed foods and sugars.
  • Stay Hydrated: Drinking enough water is essential for metabolic processes. It helps in digestion and can temporarily boost your metabolism.
  • Get enough sleep: Aim for 7-9 hours per night to balance hormones and support metabolism.
  • Manage stress: Find time for fun and relaxing activities—like painting or hanging with friends. Practice relaxation techniques like meditation or yoga to reduce stress's impact on metabolism.
  • Consult professionals: Talk to pros—doctors, trainers, or nutritionists—who can be your sidekick on this health journey.

Remember, while these lifestyle changes can positively impact your metabolism and overall well being , the concept of "metabolic age" is a general estimation and not an absolute measure of health. Genetics, underlying health conditions, and other factors also play a role. Always consult with a healthcare professional before making significant changes to your lifestyle or diet, especially if you have underlying health concerns.

Is a Low Metabolic Age Bad?

Having a low metabolic age is generally a good thing.  It means your body is working efficiently for your age, which often leads to easier weight management, better health, and more energy. But remember, it's just one factor and doesn't tell the whole story about your health. Factors like exercise, diet, and genetics also play important roles.

At What Age does Metabolism Slow Down? 

Metabolism generally starts to slow down as people get older, usually in their 20s or 30s. It becomes more noticeable in the 40s and 50s. This happens because as we age, we tend to lose muscle, which burns more calories than fat. 

Other factors that can influence metabolism include hormonal changes (such as menopause in women), reduced physical activity, and a decrease in overall energy expenditure. However, it's important to note that while metabolism may slow down with age, it doesn't mean that weight gain or health issues are possible.

Living a healthy lifestyle through regular exercise, balanced nutrition, and proper sleep can help mitigate the effects of a slowing metabolism. Consulting with a healthcare professional or a registered dietitian can also provide personalized advice and strategies for managing metabolism as one ages.

What are Metabolic Disorders?

Metabolic disorders are health conditions where the body has trouble breaking down food into energy or processing certain substances. These issues can be caused by genetic problems or enzyme deficiencies. They can lead to problems like high blood sugar (diabetes), trouble digesting certain foods (like phenylketonuria or galactosemia), or issues with storing and using energy properly in the body.

Treatment for these disorders can involve special diets, medications, or other therapies to help manage the symptoms and prevent complications. Early detection and working closely with doctors are important to keep these conditions under control.

How Do You Know If Your Metabolism is Slow or Fast? 

Determining whether your metabolism is slow or fast involves several factors and may not always be straightforward. Here are some indicators that could suggest you have a slow or fast metabolism:

  • Weight: If you find it hard to lose weight despite eating less you might have a slow metabolism. If it's hard for you to keep weight on or you easily lose weight without trying, you might have a fast metabolism.
  • Energy levels: A fast metabolism can make you feel more energetic, while a slow metabolism might make you feel tired or sluggish.
  • Hunger: Feeling hungry frequently could indicate a faster metabolism, whereas feeling full for longer periods might suggest a slower metabolism.

What’s the Difference Between Fast Metabolism and Slow Metabolism?

Differences in metabolic rates can lead to classifications of "fast metabolism" or "slow metabolism," which can impact weight management and overall health.

Fast Metabolism:

  • Calorie Burn: People with a fast metabolism tend to burn calories at a higher rate even when at rest. This means they might require more food or calories to maintain their weight.
  • Weight Management: Individuals with a faster metabolism may find it easier to prevent weight gain or lose weight because their bodies burn calories more efficiently.
  • Energy Levels: They may have higher energy levels due to quicker processing of nutrients into energy.

Slow Metabolism:

  • Burns fewer calories: Uses less energy at rest.
  • Tends to gain weight easily: Might struggle with weight gain or find it harder to lose weight.
  • Lower energy levels: Processes food into energy slowly.
  • Feels colder: Low metabolism may generate less body heat, which might make these individuals feel colder than others. 

Frequently Asked Questions:

How do I help my metabolism burn more fat?

Boosting your metabolism to burn fat involves adopting certain lifestyle changes and habits that can potentially enhance your body's ability to utilize stored fat for energy. Here are some strategies that may help:

  • Exercise More: Engage in both aerobic  exercises (like running, swimming, or cycling) and strength training (such as weightlifting). Cardio helps burn calories during the activity, while strength training builds muscle, which can boost your metabolism in the long term.
  • Eat Well: Focus on a balanced diet that includes whole foods, lean proteins, healthy fats, fruits, vegetables, and complex carbohydrates. Avoid processed foods and excessive sugar intake. Consider a diet that creates a calorie deficit to encourage the body to utilize stored fat for energy.
  • Stay Hydrated: Drink plenty of water; it helps manage hunger and boosts metabolism.
  • Get Enough Sleep: Aim for 7-9 hours of quality sleep each night.
  • Reduce Stress: Practice relaxation techniques like meditation or deep breathing.
  • Consider Intermittent Fasting: It might help regulate hunger and improve fat burning.
  • Increase Protein: Include protein in your meals to feel fuller and burn more calories digesting it.
  • Avoid Sugary Drinks: Opt for water or healthier beverages instead.

Remember, there's no magic trick to drastically change your metabolism overnight. These strategies work best when adopted as part of a sustainable lifestyle rather than as short-term solutions. Always consult a healthcare professional or a nutritionist before making significant changes to your diet or exercise routine, especially if you have underlying health conditions.

Can metabolism burn belly fat?

Yes, metabolism plays a role in burning belly fat. It's like a furnace in your body that uses calories to fuel various functions, including burning fat. When your metabolism is functioning efficiently, it helps your body burn calories, including those stored as belly fat, for energy. 

However, targeted spot reduction of fat in specific areas like the belly isn't directly controlled by metabolism alone. Overall fat loss through a combination of a healthy diet, regular exercise, and a well-functioning metabolism contributes to reducing belly fat over time.

Why am I losing weight but eating more?

??You might be losing weight while eating more because the quality or types of food you're consuming could be different. Factors like increased physical activity, a change in metabolism, or a medical condition can also affect weight loss despite eating more.

Back to blog

Leave a comment

Please note, comments need to be approved before they are published.