What You Should Know About Metabolism

What You Should Know About Metabolism

You have probably come across the word metabolism at some point but may not have known its significance to your health.

The common message that you have heard is that if yours is too slow you may gain weight.  But what does this all mean?

From biological standpoint, “metabolism” is used to describe all of the biochemical reactions in the body.  It’s how you take in nutrients and oxygen and use them to fuel everything that you do.

Your body has an incredible ability to grow, heal, and generally stay alive.  And without this amazing biochemistry you would not be possible.

Metabolism includes how the cells in your body:

  • Store excess energy for later use
  • Fuel activities you can’t control such as wound healing, heart beat, processing of nutrients & toxins and other
  • Fuel activities you can control for example physical activity

So when you put all of these activities together into your metabolism you can imagine that these processes can work too quickly, too slowly, or just right.

Which brings us to the “metabolic rate”.

What is Metabolic rate?

This is how fast your metabolism works and is measured in calories (yup, those calories!).

The calories you eat can be used for:

  • Heat from all those biochemical reactions
  • Storage of extra leftover “unburned” calories as fat
  • Work such as exercise and other activities

As you can imagine the more calories you burn as work or creating heat, the easier it is to lose weight and keep it off because there will be fewer “leftover” calories to store for later.

There are a couple of different ways to measure metabolic rate.  The first one is the “resting metabolic rate” or RMR, which is how much energy your body uses when you’re not being physically active.

The second one is the “total daily energy expenditure” or the TDEE, which measures both the resting metabolic rate as well as the energy used for “work” (for example exercise) throughout a 24-hour period.

What affects your metabolic rate?

In a nutshell: a lot!

The first thing you may think of is your thyroid.  This gland at the front of your throat releases hormones to tell your body to “speed up” your metabolism.  Of course, the more thyroid hormone there is the faster things will work and the more calories you’ll burn.

But that’s not the only thing that affects your metabolic rate.

How big you are counts too!

Larger people have higher metabolic rates; but your body composition is crucial!

As you can imagine muscles that actively move and do work need more energy than fat does.  So the more lean muscle mass you have the more energy your body will burn and the higher your metabolic rate will be.  Even when you’re not working out.

This is exactly why weight training is often recommended as a part of a weight loss program.  Because you want muscles to be burning those calories for you.

The thing is, when people lose weight their metabolic rate often slows down which you don’t want to happen.  So you definitely want to offset that with more muscle mass.

Aerobic exercise also temporarily increases your metabolic rate.  Your muscles are burning fuel to move so they’re doing “work”.

The type of food you eat also affects your metabolic rate!

Your body actually burns calories to absorb, digest, and metabolize your food.  This is called the “thermic effect of food” (TEF).

You can use it to your advantage when you understand how your body metabolizes foods differently.

Fats, for example increase your TEF by 0-3%; carbs increase it by 5-10%, and protein increases it by 15-30%!  By trading some of your fat or carbs for lean protein you can slightly increase your metabolic rate. A big win for you!

Another bonus of protein is that your muscles need it to grow.  By working them out and feeding them what they need they will help you to lose weight and keep it off.

And don’t forget the mind-body connection.  There is plenty of research that shows the influence that things like stress and sleep have on the metabolic rate.

This is just the tip of the iceberg when it comes to metabolism and how so many different things can work to increase (or decrease) your metabolic rate.

Recipe (Lean Protein): Lemon Herb Roasted Chicken Breasts (Serves 1)

  • ½ lemon, sliced
  • ¼  tablespoon rosemary
  • ¼  tablespoon thyme
  • ½ cloves garlic, thinly sliced
  • 1 chicken breasts (boneless, skinless)
  • dash salt & pepper
  • ¼  tablespoon extra virgin olive oil

Preheat oven to 425F.  Layer ¼ of the lemon slices on the bottom of a baking dish.  Sprinkle with ¼ of the herbs and ¼ of the sliced garlic.

Place the chicken breasts on top and sprinkle salt & pepper.  Place remaining lemon, herbs and garlic on top of the chicken.  Drizzle with olive oil.  Cover with a lid or foil.

Bake for 45 minutes until chicken is cooked through.  If you want the chicken to be a bit more “roasty” then remove the lid/foil and broil for another few minutes (watching carefully not to burn it).

Serve & enjoy!

Tip: You can add a leftover sliced chicken breast to your salad for lunch the next day!

In Health,

Dr. Anna ND


  1. 10 Easy Ways to Boost Your Metabolism (Backed by Science) https://authoritynutrition.com/10-ways-to-boost-metabolism/
  2. All About Energy Balance http://www.precisionnutrition.com/all-about-energy-balance