Let me start with, metabolism is a complex series of events, processes, chemical reactions and conversions that is widely just as understood as it is misunderstood. There would be no possible way for me to even begin to fully understand metabolism as I am not a scientist, however, we can distill it down to layman's terms and get a decently vague grasp on it. It is the interactions between and the roles of and responses to your hormones, behavior and environment. Okay, let's get into it..
Wikipedia defines it as “ the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks of proteins, lipids, nucleic acids, and some carbohydrates; and the elimination of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transportation of substances into and between different cells.”
Read that again... "the sum of all chemical reactions that occur in living organisms."
Okay, so… how do so many normal people determine their metabolism is slow? Is it running a race? Did it get tired? Did it get stuck somewhere?
Right.. We have no idea what it means when we decide our metabolism is “slow”. We would need a lab and some scientists for that. And even they wouldn't know what "slow" means.
What is actually happening when an otherwise healthy person thinks their metabolism is slow?
(Colors correspond with image below)
Lower BMR
Less metabolically active tissue (i.e. less muscle tissue, more fat tissue)
You are too sedentary
You don’t eat enough and exercise too much or at too high of an intensity, therefore forcing your body into adaptations that slow down or stop non essential body processes and functions
Or you are not eating in ideal proportions for you (macronutrients).
What do all of these things have in common? WE have control over them AND WE can change them! Let’s unpack this!
(Also hormones, but that is for a physician and not something we can always address on our own. This would be metabolic disorders and/or dysfunction. So we will leave that to the professionals and will not discuss in this article.)
First let’s look at what TDEE is!
Total Daily Energy Expenditure. This means how much energy (calories) you’ll use throughout your day. It is broken down into 4 Parts:
BMR (70%) - Basal Metabolic Rate: the energy (calories) your body uses at complete rest
NEAT (15%) - Non Exercise Activity Thermogenesis: The energy (calories) your body uses while you go about your day. Walking through the parking lot, doing laundry, cooking dinner, doing yard work, etc. All of your activity outside of Intentional and planned activity like sports and lifting weights.
EAT (5-10%) - Exercise Activity Thermogenesis: The energy (calories) you burn during intentional activity like sports and lifting weights.
TEF (5-10%) - Thermic Effect of Food: The energy (calories) it takes to digest the food you eat.
We can manipulate each one of these to maximize energy (calorie) burn throughout the day!
So how do we do that?
BMR - Basal metabolic rate: is the measure of energy (calories) your body uses at complete rest. This accounts for around 70% of our daily energy expenditure (or calories burned).
How do we change our BMR? Well, as your weight changes, so does your BMR. It takes less energy to move a 130lb person than it does a 300lb person. But it goes deeper than that. It takes more energy to move a 130lb person with 100lbs of lean muscle tissue than it does to move a 130lb person with 50lbs of lean muscle tissue.
Muscle is metabolically active. This means it requires energy to maintain it whereas fat tissue does not. Muscle requires energy to contract and relax, fat tissue does not. Therefore the more lean muscle tissue you have, the more energy (calories) your body requires to function and consequently the higher your BMR will be.
NEAT - Non Exercise Activity Thermogenesis: The energy (calories) your body uses while you go about your day. Walking through the parking lot, doing laundry, cooking dinner, doing yard work, etc. All of your activity outside of Intentional and planned activity like sports and lifting weights. This has far more of an impact on daily energy burn that any planned exercise session!
This accounts for around 15% of our daily energy expenditure (or calories burned). To influence or manipulate this we do things like count our steps encouraging us to be more active throughout the day. Take the stairs instead of the elevator. Park in the back of the parking lot instead of trying to find the closest parking space. Take walk breaks throughout the day, especially if you have a sedentary job. Also things like fidgeting or dancing rather than standing still, playing with the kids at the playground instead of sitting on the bench, swimming instead of laying on the shore, ANY kind of activity that isn’t a planned workout. Notice this accounts for much more than our planned activities like sports, lifting weights and our gym sessions!
For more on this, check out this article!
TEF - Thermic Effect of Food: The energy (calories) it takes to digest the food you eat. Remember in the definition of metabolism, it includes digestion! It takes energy to break down the foods we eat. Each different kind of food takes a different amount of energy. Some take more, some take less.
Protein takes the most energy to breakdown and shuttle out to wherever it needs to go at 20-30%. Carbohydrates are next at 5-15% and Fat takes the least amount of energy to digest at 0-3%.
To influence or manipulate this, eat more protein, moderate carbohydrates and moderate fats! (I know... it's always more protein, isn't it?!)
** TEF and EAT can vary between 5-10% depending on how much you do of both.
EAT - Exercise Activity Thermogenesis: The energy (calories) you burn during intentional activity like sports and lifting weights.
Notice this accounts for the LEAST amount of your TDEE and typically we see people put the MOST emphasis on this one. This is important! This builds the muscle we need to increase our BMR. This keeps our bones strong and dense. This helps our balance, mood, confidence and coordination! This is important for many reasons, but energy (calorie) burn is not one of them!!
Beyond this, one more factor that may lead to weight gain or difficulty losing weight (fat specifically) would be keeping yourself in a chronic calorie deficit.
For more on this and how more time doesn't always equal more calories, read this article!
Now you know!
Your metabolism does not know how to be slow.. it just responds to the way you live your life, your environment and your hormones! You cannot "speed up" your metabolism, but you can change things you do in your daily life that your metabolism responds to.
Does spicy food or thermogenic foods increase your body temperature and cause you to burn calories, sure, maybe, who knows, but this ain't it, friends!
Outside of hormonal imbalances, the things listed above are the real "metabolism boosters". Focus your energy here!!