Metabolism 101

Metabolism has become quite a buzzword amongst people chasing fitness goals.

You must have encountered at least one person cribbing about how slow or fast their metabolism is, and also blaming it for not being able to maintain their “ideal” body weight.

Well, what most of us don’t know is that metabolism impacts not just the body weight but also performs multiple biological functions taking place in the body:

  • maintaining the health of organs like heart and liver
  • balancing the hormones
  • regulating blood sugar levels
  • controlling your circadian rhythm (sleep–wake cycle) and other brain functions
  • maintaining reproductive health, digestive health, and immunity

So, Dr. YOU is here to simplify the science of metabolism, given how fundamental it is to your physical and mental well-being.

What is metabolism?

Metabolism can be defined as a dynamic process involving all the biochemical reactions taking place in each and every cell of your body to sustain life.

We need to understand a bit of nutrition to comprehend the science of metabolism.

Your food is made of macronutrients and micronutrients:

  • Macronutrients (carbohydrates, fats, and protein) are the nutrients that your body needs in larger amounts as they provide calories and form body tissues.
  • Micronutrients (vitamins and minerals) are the nutrients that your body needs in smaller amounts.

Vitamins (A, C, D, E, B vitamins, etc.) and minerals (iron, calcium, zinc, copper, selenium, manganese, etc.) don’t provide calories but play some very important roles in immunity, metabolism, and maintaining body tissues.

The process of digestion of food in your intestine breaks down:

  • Carbohydrates to glucose
  • Fats to fatty acids
  • Proteins to amino acids

Each of these macronutrients contribute a specific amount of calories, which your body burns (with the help of chemical reactions) to release energy. Metabolism involves an interplay of energy between catabolism and anabolism.

Before you get scared of the overload of scientific terms, let’s further break them down:

  • Catabolism is the breakdown phase of metabolism in which macronutrients that we consume from our food (carbohydrates, proteins, and fats) or those stored in body tissues are converted into energy.
  • Anabolism is the build-up phase of metabolism, which requires consumption of energy to form body tissues, proteins, enzymes, hormones, and energy stores.

Total daily energy expenditure (TDEE)

You would be surprised to know that you burn more calories at rest than when you are physically active. To better understand this, you will have to understand how your body expends energy on a daily basis. Your Total Daily Energy Expenditure (TDEE) involves four components:

  1. Basal metabolic rate — It’s the amount of calories that your body burns at rest (12–15 hours after your last meal) to release energy for life-sustaining processes like breathing and respiration, heart beat and blood circulation, cellular repair, maintaining body temperature, etc. BMR accounts for about 60% of your daily energy expenditure.
  2. Thermic effect of food — It’s the amount of calories your body burns to digest, absorb, and store the nutrients of the food that you have eaten. TEF accounts for about 10% of your daily energy expenditure.
  3. Non-exercise activity thermogenesis — It’s the amount of calories your body burns to support activities outside of exercise, sleeping, and digestion. This is energy spent on daily tasks like walking, cleaning, cooking, washing, bathing, typing or even talking and fidgeting. NEAT accounts for about 10% of your daily energy expenditure. It’s a variable component that you can change by consciously becoming more physically active throughout the day.
  4. Exercise activity thermogenesis (EAT) — It’s the amount of calories your body burns when you perform physical activities like running, jogging, strength training, etc. that increase your heart rate and work on your muscles. EAT accounts for about 20% of your daily energy expenditure.

Having a fast metabolism or high metabolic rate means your body uses food for fuel quickly instead of storing it as fat. But you can still gain weight if you consume more calories than your body burns and if you lead a sedentary lifestyle.

You need to optimize your metabolism not just to lose weight but also for overall health, as any disorder in metabolism can eventually spiral into metabolic syndrome. This is characterized by high blood pressure, high cholesterol, high blood sugar, visceral abdominal fat, and chronic inflammation. You can read more about this highway to hell-th problems in our previous blog.

Remember, the only person who can keep YOU the healthiest is YOU!

DISCLAIMER: Dr. YOU aims to bring you the latest evidence-based science, and our content is for informational purposes only. The content is not medical advice or guarantee of an outcome. You should always consult a doctor or qualified healthcare professional if you need further clarification and before making any changes to your treatment plans and lifestyle, or that of others.

Dr. YOU is a one-stop platform to address the health information needs of health consumers. Our goal is to arm people with the information necessary to make meaningful decisions regarding their health and nudge behaviour change.

With our combined experience of two decades in research and healthcare, we built the Dr. YOU platform around the WHO-endorsed “Best Buy” intervention design for preventing and managing chronic diseases.

Follow us on Medium (@drYOUofficial) and Instagram (@dr.YOU_official) for the latest content and updates.




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