Metabolism 101: Everything You Need To Know



Written by: Kat Gal

Your metabolism is something that you likely talk about quite frequently. If you gain weight, you blame it on your metabolism. You fear that dieting might have slowed your metabolism, but hope your next lifestyle change will speed it up again. You look for exercise methods and food options that will help speed up your metabolism.

But do you actually know what your metabolism is, how it works and how to boost it?

If you are not sure, don’t be embarrassed, most people have no idea. Read on to learn everything you need to know about your metabolism.

Metabolism 101

What Is Your Metabolism?

Your metabolism is not an organ, like your lungs or your heart and is not a system, like your digestive system or endocrine system; it is also not a thing, like a cell or a molecule. Your metabolism is a process.

Your metabolism is the combination of physical and chemical processes in your body that are needed to keep you alive. It includes natural processes that produce energy for your body to function and do everything it needs to do.

How Does Your Metabolism Work?

How does your metabolism know how fast or slow to produce energy for you? This is where your thyroid comes into the picture.

You can look at your thyroid like it is a company. The thyroid sort of moderates your metabolism, acting as a coordinator. Its job is being overseen by a manager, the pituitary gland. All the work is being directed by the CEO, your hypothalamus. Your hypothalamus is the one that sends messages to your pituitary gland so that it can pass signals down to your thyroid to release the appropriate hormones.

These hormones are the ones that are responsible for the speed of your metabolism. Your thyroid-stimulating hormone (TSH) produced by the pituitary is very important in the process as it prompts the release of T4 and T3.

Too much T4 in your system means that your thyroid activity will slow down, whereas too little T4 will increase your TSH levels. It is important to keep T4 and T3 levels in your blood balanced and constant to keep your metabolism functioning properly.

What Affects Your Metabolism?

You metabolism can be affected by the following:

  • Sex
  • Age
  • Diet
  • Body composition
  • Overall lifestyle
  • Physical activity levels
  • Sleep

Though you cannot change your age and cannot completely change all aspects of your sex, you can change and control all other areas.

It is incredibly important to provide your body with the adequate and necessary fuel, otherwise known as energy, to allow all the processes to run properly.

About 60-70% of your total daily energy expenditure (TDEE) can be calculated based on your age, sex, height, weight and activity levels, giving you your Basal Metabolic Rate (BMR). You can get an estimate of your BMR and TDEE using online tools.

What Are Your Calories Being Used For And Can You Speed Up Your Metabolism?

I bet that you are anxiously waiting for me to give you tips on how to speed up your metabolism. I have good news: there are some super awesome ways you can increase your metabolism.

First let’s look at what the calories – the energy – you are consuming are being used for:

  • 60 – 70% is used for vital functions keeping you alive, such as your heart rate, breathing and body temperature. Now that you have probably calculated your BMR and see that a large percentage of it is used used for basic functions that you need to survive, you can understand why are low-calorie diets are dangerous and that an apple a day is really not enough.
  • 15 – 30% of calories are being used for physical activities, anything from housework, walking, gardening, exercising, running after the kids, etc.
  • 10 – 15% is being used for your digestion. Yep, you are actually burning calories while you are digesting, breaking down food and drinking. The calories burn into a form that can be used by your body to function, renew and repair properly.

Now that you see that most of your energy intake is being used just to exist and that you can increase your metabolism by exercising, moving and eating regularly, let’s move on to foods and tactics that can help you to fire up your metabolism and keep you at a healthy weight.

Foods And Tactics That Support Your Metabolism:

  • Eating a whole foods diet, with a limited amount of processed foods or no processed foods at all.
  • Drinking at least 8 – 10 glasses of 8 oz water throughout the day.
  • Eating plenty of leafy greens, vegetables and fruits full of vitamins, minerals and fiber
  • Eating healthy fats, such as nuts, seeds, coconut oil and avocados, avoiding saturated fat, such as butter, lard, vegetable oil and bacon.
  • Choose lean protein sources, preferably from plant sources, such as beans, legumes and seeds. If you consume animal products, opt for fish and lean meat from organic sources.
  • Watch your hunger signals and your portion sizes. Eat slowly and mindfully. Practice intuitive eating. Eat until you feel satisfied, but not full. If you are not used to it, this may take practice, but with patience you will get the hang of it quickly.
  • Consume iodine rich foods such as seaweed and seafood. You can get tested for iodine and, if necessary, you can take iodine supplements. Do not take supplements without consulting your doctor and getting a blood test.
  • Consume selenium regularly. It is excellent for thyroid function. 2 brazil nuts a day is enough to take care of your needs, but sunflower seeds, mushrooms and for non-vegetarians, tuna, crab and lobster are good options too.
  • Avoid soy products as much as possible as they can have a goitrogenic effect on your thyroid.
  • If you consume cruciferous vegetables, including broccoli and cabbage, cook them instead of eating them raw.
  • Get enough vitamin D through sunshine and supplementation. Low vitamin D levels are associated with thyroid problems.
  • Keep moving your body. Exercising and living an active lifestyle can not only boost your metabolism, but can reduce your risk of many health conditions and boost your happiness levels as well.

What is the most important thing you have learned about your metabolism today? If you have any questions, comments, or tips, please leave them in the comments below, we would love to hear from you!


Kat Gal

Kat Gal

Health Writer & Freelance Writing Mentor at Kat Gal Writer / Freelance Writer School
Kat Gál is a holistic health writer who helps health, wellness, and nutrition businesses to market their products and services through quality online content. She is also a freelance writing mentor teaching wanna-be-freelancers how to make a living writing at Reach out if you are looking for amazing blog content at or Visit for freelance writing tips. Follow me on Instagram @freelancewriterschool and on Facebook at
Kat Gal


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Glenn was in an accident with a hockey puck that made it so his mouth had to be wired shut! While he was going through recovery he found that Organifi Protein sustained him in a healthy way where he was able to maintain his muscle mass while still be able to loose weight.

-Tragedy Turns to Opportunity, Weightloss and Holistic Health
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