Why Your Metabolism Matters When It Comes to Your Weight & Energy
The word “metabolism” is thrown around a lot these days.
You’re told that if it’s too slow you might gain weight. But what exactly does this all mean?
Technically “metabolism” is the word to describe all of the biochemical reactions in your body. It's how you take in nutrients and oxygen and use them to fuel everything you do.
Your body has been designed perfectly and has an incredible ability to grow, heal, and carry you through this beautiful life! It is always working for you despite what some may have you believe and it has one mission…to keep you ALIVE! Without this amazing biochemistry you would not be possible.
Some basics
Metabolism includes how the cells in your body:
Allow activities you can control (e.g. physical activity etc.).
Allow activities you can't control (e.g. heart beat, wound healing, processing of nutrients & toxins, etc.).
Allow storage of excess energy for later.
So when you put all of these processes 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”.
Metabolic rate
This is how fast your metabolism works and is measured in calories (yup, those calories!).
The calories you eat can go to one of three places:
Work (i.e. exercise and other physical activity)
Heat (i.e. from all those biochemical reactions – think hormones, nervous system, digestion etc)
Storage (i.e. extra leftover “unburned” calories stored as fat)
So logic says 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…
I personally find this to be way too simplistic, but just know that is the theory.
There are a couple of different ways to measure metabolic rate. One is the “resting metabolic rate” (RMR) or basal metabolic rate (BMR) which is how much energy your body uses when you're not being physically active.
The other is the “total daily energy expenditure” (TDEE) which measures both the resting metabolic rate as well as the energy used for “work” (e.g. exercise) throughout a 24-hour period.
What affects your metabolic rate?
In a nutshell: a lot!
I cover off some important factors in a post I wrote here including reasons why the calories in, calories out equation isn’t the be-all end-all when it comes to metabolism.
A common area of discussion around metabolism that you might be familiar with is your thyroid. This gland at the front of your throat releases hormones to tell your body to “speed up” your metabolism. The more thyroid hormones are released into the blood the more your metabolic rate increases.
But that's not the only thing that affects your metabolic rate.
Size matters.
How big, or little, you are counts too.
Larger people have higher metabolic rates; but body composition is a crucial piece of the puzzle too. 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 or resistance 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.
Whilst hitting the weights section at the gym would be ideal, this doesn’t need to be the case for many of us who just don’t have enough hours in a day to make it! There are plenty of at home workouts you can do using your body weight as resistance. Yoga and pilates are great options and a beautiful way to promote lean muscle while also helping to reduce stress levels (which can impact metabolism and weight too).
Aerobic (cardio) exercise also temporarily increases your metabolic rate. Your muscles are burning fuel to move so they're doing “work”. So a light jog around home if you’re WFH or brisk walk is a great choice.
Food matters.
It probably doesn’t come as a surprise that the type of food you eat also affects your metabolic rate!
Your body actually burns calories to absorb, digest, and metabolise 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.
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.
And lastly, a loving reminder that this is not about burning as many calories as you can or getting ripped. I’m not a personal trainer. This is just about being human and honoring what you need to take care of yourself and understanding how your body is working for you.
If you want my help to find ways you can learn more, connect with yourself, move through stressful days more effectively, and have the energy to be your best self then let’s chat. Here’s the link to book your free 30min health strategy call with me xx
Sources:
Tortora, G. J., Derrickson, B., Burkett, B., Peoples, G., Dye, D., Cooke, J., Diversi, T., McKean, M., Samalia, and L., Mellifont, R. (2019). Principles of Anatomy & Physiology (2nd ed.). Milton, QLD: John Wiley & Sons Australia.