Understanding Metabolism: How It Works and What You Can Do to Improve It

Have you ever wondered why some people seem to be able to eat whatever they want without gaining weight, while others struggle to keep off the pounds, no matter how hard they try?

The answer lies in metabolism – the complex biochemical process that converts food into energy and affects weight loss and gain.

Understanding metabolism is an essential component of achieving your weight loss, muscle gain, or overall health goals.

In this article, we’ll explore the following:

  • The science behind metabolism,
  • How it works
  • What you can do to boost metabolism

What is Metabolism

The body’s metabolism is a chemical process that occurs in the cells of the body to convert the food and drink you consume into energy. During this complex process, calories in food and beverages are combined with oxygen to release the energy, which your body needs to function.

A faster metabolism means your body burns more calories, even at rest. So, it’s no surprise that a sluggish metabolism can make it harder for you to lose weight.

Thousands of metabolic reactions happened at the same time. All of them were controlled by the body to keep our cells healthy and working.

Your metabolism plays a crucial role in weight loss because it determines how many calories your body burns at rest. This is known as your basal metabolic rate (BMR).

What is Metabolism

What Does Your Metabolism Do?

Your metabolism never stops, even when you are at rest. It constantly provides energy for basic body functions, such as:

  • Breathing.
  • Digesting food.
  • Circulating blood.
  • Repairing and renewing cells.
  • Controlling body temperature.
  • Triggering muscle contraction.
  • Eliminating waste through urine.
  • Maintaining brain and nerve functions.

A faster metabolism means a higher BMR, which means your body burns more calories even when you’re not active.

What is Metabolism

What Is Basal Metabolic Rate (BMR)

BMR (Basal Metabolic Rate) is the amount of energy (measured in calories) that the body needs to perform vital functions while at rest.

These functions include breathing, blood circulation, cell production, and other processes necessary to keep us alive.

The body burns calories even when at rest in order to carry out these essential functions. It is influenced by various factors, such as age, gender, body composition, genetics, and hormones.

For most people, the normal daily activity requirement is about 70% of total energy (calories) each day. Physical activity accounts for nearly 20% of expenditure, while digestion accounts for about 10%.

Your BMR can help you determine how many calories you need to consume each day to maintain your weight, lose weight, or gain weight.

What Is Basal Metabolic Rate (BMR).
Know Your BMR: Try Our FREE BMR Calculator

How Metabolism Works

The body’s metabolism works through two processes, namely catabolism, and anabolism, which take place simultaneously. The following is the explanation:

1. Catabolism

The process of catabolism breaks down food molecules into smaller molecular compounds, which releases energy from them.

  • Carbohydrate catabolism: Complex carbohydrates are broken down into glucose through digestion, and glucose is further metabolized to produce energy.
  • Lipid catabolism: Fats are broken down into fatty acids and glycerol, which can be used as an energy source.
  • Protein catabolism: Proteins are broken down into amino acids, which can be used for energy or to build new proteins.

2. Anabolism

Anabolism does the opposite. This process involves the synthesis of larger molecules from smaller ones, requiring energy. Examples include:

  • Carbohydrate anabolism: Glucose molecules are combined to form glycogen, which is stored in the liver and muscles for future energy needs.
  • Lipid anabolism: Fatty acids and glycerol are combined to form triglycerides, which are stored in adipose tissue as a long-term energy reserve.
  • Protein anabolism: Amino acids are assembled to form new proteins that are essential for cell growth, repair, and various physiological functions.

3. Metabolic Pathways

These are interconnected sequences of chemical reactions that occur within specific organelles or regions of cells. Some important metabolic pathways include:

  • Glycolysis: The breakdown of glucose to produce energy in the form of ATP.
  • Krebs cycle (Citric Acid Cycle): This cycle occurs in the mitochondria and generates ATP by oxidizing acetyl-CoA, derived from various fuel sources.
  • Electron transport chain: It is the final step in cellular respiration, where electrons from NADH and FADH2 are passed along a series of protein complexes to generate ATP.
  • Gluconeogenesis: The synthesis of glucose from non-carbohydrate sources like amino acids and glycerol when glucose is scarce.

4. Enzymes

These are biological catalysts that facilitate metabolic reactions by lowering the activation energy required for a reaction to occur.

Enzymes play a critical role in accelerating metabolic processes without requiring a significant amount of energy.

5. Hormones

A number of hormones control metabolism by changing the activity of enzymes and the rate at which they work.

  • Insulin: Regulates carbohydrate and lipid metabolism, promoting glucose uptake and storage of excess nutrients.
  • Glucagon: Stimulates the breakdown of glycogen to release glucose and promotes gluconeogenesis.
  • Thyroid hormones: Thyroxine (T4) and triiodothyronine (T3) regulate metabolic rate, affecting the overall speed of metabolism.

Metabolism Calculator

A metabolism calculator is a tool that estimates your Basal Metabolic Rate (BMR), which is the number of calories your body needs to maintain basic functions at rest.

BMR represents the energy expenditure required to support vital bodily functions such as breathing, circulation, and organ function.

Try our free metabolism calculator to determine your calories’ requirement for weight management.

Fast Metabolism vs Slow Metabolism

Basal Metabolic Rate (BMR):

  • People with a fast metabolism tend to have a higher BMR, which means they burn more calories at rest.
  • A slower metabolism results in a lower BMR, which results in fewer calories burned at rest.

Caloric Intake

  • People with a fast metabolism can consume more calories without gaining weight because their bodies efficiently burn through the energy.
  • A slow metabolism can make you more likely to gain weight, as your body stores extra calories as fat instead of burning them quickly.

Weight Loss

  • Fast Metabolism helps people lose weight easily, because their bodies naturally burn calories at a higher rate.
  • People with a slower metabolic rate may experience difficulty in losing weight, as their bodies require fewer calories to perform essential functions.

Muscle Mass

  • Higher muscle mass tends to have a faster metabolism, since muscle tissue requires more energy to maintain.
  • Lower muscle mass can lead to a slower metabolism because they have less metabolically active tissue.

Genetics and Age

  • Some individuals may have genetically inherited a faster metabolism, allowing them to naturally burn calories more efficiently.
  • Genetics can also play a role in a slower metabolism. Additionally, as people age, their metabolism tends to naturally slow down.

Lifestyle Factors

  • Regular physical activity, especially strength training, can help you build lean muscle mass.
  • A sedentary lifestyle and lack of exercise can lead to a slower metabolism.
Want to take your gains to the next level? Discover your daily calorie needs with our free TDEE calculator

Signs of a Slow Metabolism

If you have a slow metabolism, you may find it difficult to lose weight, even if you’re eating a healthy diet and exercising regularly. Some signs of a slow metabolism include:

  • Feeling tired and sluggish
  • Difficulty losing weight
  • Feeling cold all the time
  • Low-energy levels
  • Constipation
  • Dry skin
  • Hair loss
  • Irregular menstrual periods (in women)

If you’re experiencing these symptoms, it’s important to speak with your doctor to rule out any underlying medical conditions that could be affecting your metabolism.

Know Your Calories Requirement To Lose Weight

Things That Affect Body Metabolism

The metabolic rate or how many calories your body burned to produce energy generally varies from person to person. 

There are the following factors that influence metabolism and weight loss.

1. Body size and composition

People having bigger and more muscular bodies are able to burn more energy, even when resting. This is because muscle tissue is more active in the metabolic process than fat tissue.

2. Gender

Male bodies usually burn more energy than women. This is because men often have more muscle tissue and less body fat when compared to women.

3. Age

As we get older, the amount of muscle tends to decrease, and the number of fat increases. This can slow down the metabolic process or burning calories to produce energy.

4. Genetic

Genetic or hereditary factors can affect the growth and size of muscle tissue. This will later be able to influence the burning of energy or metabolism of one’s body.

5. Body temperature

Metabolism will naturally increase when body temperature decreases (hypothermia) or when the body is cold. It aims to increase body temperature to return to normal so that the body’s organs can function properly.

6. Caffeine Intake or Stimulants

Metabolism can be increased if you consume drinks that contain stimulants such as caffeine. This substance is naturally found in coffee and tea. 

In addition, the body’s metabolism can also be increased when taking drugs that have stimulants.

7. Hormones

The hormone that functions to regulate the body’s metabolism is the thyroid hormone. Therefore, disruption of the production or action of thyroid hormone can increase or decrease the body’s metabolism.

8. Pregnancy

Metabolism in a pregnant woman’s body will increase to support the process of growth and development of fetal organs and tissues. The metabolic process will usually begin to increase when the pregnancy reaches the age of 15 weeks until entering the third trimester.

9. Thermic Effect of Food (TEF)

The process of digesting, absorbing, spreading, and storing food nutrients also needs calories as fuel. The body uses about 10 percent of calories for this food processing.

Different macronutrients have varying effects on TEF, with protein having the highest thermic effect, followed by carbohydrates and fats.

10. Physical Activities and sports

In addition to sports, simple activities such as playing with pets, walking to the stalls, routine walking in the afternoon can also burn calories, of course, in different amounts.

Exercise increases energy expenditure, both during the activity and afterward, as your body repairs and rebuilds tissues.

How to Improve Your Metabolism

Having a high metabolic rate does make the body be able to burn more calories and reduce fat. A high metabolic rate also makes you feel better because the body gets enough energy supply to carry out its various functions. 

Here are some ways to increase the body’s metabolism for the diet which have been proven by the nutrition experts through various studies.

1. Get Sufficient Sleep

The study has shown that sleep loss can disrupt the regulation of energy balance and contribute to weight gain and obesity.

When you don’t get enough sleep, your body produces more ghrelin, a hormone that triggers hunger and cravings for sugary and high-calorie foods.

Additionally, lack of sleep can also lead to fatigue, which can make it harder to stick to an exercise routine.

2. Do High-intensity interval training (HIIT)

HIIT, is a form of interval training, a cardiovascular workout involves alternating between short, intense bursts of exercise and brief recovery periods.

HIIT workouts provide improved athletic capacity and condition, as well as improved glucose metabolism.

3. Do Strength Training

Strength training usually involves lifting weights or doing exercises that challenge your muscles and take a lot of effort.

These intense workouts demand more energy and can increase your metabolic rate both during the workout and afterward as your body recovers.

Working out muscles not only helps you lose weight, but it also keeps your muscles strong and healthy.

4. Stay Active Throughout the Day

Look for opportunities to increase your daily activity level. Take regular breaks from sitting and incorporate more movement into your day.

This can include walking or biking instead of driving, taking the stairs instead of the elevator, or simply adding short walks after meals.

5. Eat Protein In Every Meal

Eating more protein is one of the most effective ways to aid fat loss and muscle building.

Protein is a nutrient that helps to keep you full and satisfied for longer periods of time, which can help to reduce overall calorie intake.

Protein is a type of food that burns more calories in the digestive process than carbohydrates and fats. 

Eat More Protein

6. Drink Plenty of Water

Drinking water can increase your metabolism. Especially if the water is cold because the body needs more calories to raise the temperature of the water when it enters the body. 

In addition, drinking water before meals will make you full faster, making it easier to control portions of food. 

If you get bored with its tasteless taste, you can try drinking tea, for example, oolong tea and green tea.

7. Manage Stress Levels

Chronic stress can contribute to hormonal imbalances, including an increase in cortisol, which can negatively impact metabolism and weight management.

Stress can influence appetite and food intake. Some individuals may experience increased cravings for high-calorie, sugary, and fatty foods during stressful periods.

Incorporate stress-reducing activities into your routine, such as meditation, deep breathing exercises, or engaging in hobbies that bring you joy.

7. Use Smaller Plates

Using smaller plates can be an effective way to control portion sizes and aid weight loss.

When you use larger plates, it’s easy to serve and eat more food, leading to consuming more calories than necessary.

By using smaller plates, you can help to reduce your portion sizes, which can help to reduce overall calorie intake.

Use Smaller Plates


Metabolism booster supplements?

Here are some popular metabolism booster supplements based on studies and experience.

  • Caffeine
  • Green tea extract
  • Capsaicin
  • Guarana extract
  • Yohimbine
  • Raspberry ketones
  • Garcinia cambogia
  • Forskolin
  • Bitter orange extract
  • L-carnitine

Best Foods to Boost Your Metabolism

Here are some foods that may help your metabolism.

  • Green tea
  • Coffee
  • Spicy peppers (e.g., chili peppers, cayenne pepper)
  • Ginger
  • Cinnamon
  • Whole grains (e.g., oats, brown rice, quinoa)
  • Lean proteins (e.g., chicken breast, turkey, fish, tofu)
  • Legumes (e.g., lentils, chickpeas, black beans)
  • Leafy green vegetables (e.g., spinach, kale, broccoli)
  • Berries (e.g., blueberries, strawberries, raspberries)
  • Citrus fruits (e.g., oranges, lemons, grapefruits)
  • Nuts and seeds (e.g., almonds, walnuts, chia seeds)
  • Greek yogurt
  • Eggs
  • Water (staying hydrated can support metabolic function)

Best Supplements To Increase Metabolism

1. Vitamin B-Complex

Includes B vitamins such as B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin).

They are involved in energy production and metabolism of carbohydrates, proteins, and fats.

2. Vitamin D

It supports metabolism by enhancing calcium absorption and promoting bone health.

Research shows that vitamin D may help people with diabetes control their blood sugar and improve their insulin resistance.

3. Vitamin C

It acts as an antioxidant and supports the production of carnitine, which is a compound involved in fat metabolism.

It also assists in the absorption of iron, which is essential for energy production.

4. Vitamin E

Another antioxidant that helps protect cells from damage. It may also support energy production and metabolism.

5. Magnesium

While not a vitamin, magnesium is an essential mineral that contributes to hundreds of enzymatic reactions in the body, including those involved in energy production and metabolism.


Metabolism is a complex process that plays a critical role in weight loss, weight management, and overall health and wellbeing.

By making small changes to your lifestyle, you can boost your metabolism and become a healthier, happier you.

Remember that weight loss is a process that takes time, effort, and consistency to see results.

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