Most of us misunderstand metabolism. We talk about metabolism like it's something we can manipulate by gulping a pill, downing some green tea, or running faster. You've seen the articles headlined "Boost your metabolism" or "Try this high-metabolism diet to lose weight."
It's also a lot of peoples favorite scapegoat for their lack of weight loss success and ultimately believe that their metabolic rate cannot be changed. How many times have you heard, "I just have a slow metabolism..."
But this obscures many truths about this essential, yet still somewhat mysterious, biological process.
Here are some facts to help you understand metabolism and energy balance, and how to think about it in the context of weight gain and weight loss. Spoiler alter! There are some strategies we can utilize to positively effect our metabolism.
Calories are units of energy. And energy balance, over time, determines if you gain or lose mass (weight). The type of mass you gain is determined by lots of factors, which I will explain as we go along. But when you are trying to change the amount of mass—the solid tissue that includes your muscle, bones, organs, and fat—the outcome depends on your ability to manage the energy coming in versus energy going out (with an emphasis towards quality of energy coming in which we will talk about in future posts).
In the short term, all kinds of issues can mask your body's actual energy balance. The first being water which is between 45 and 65 percent of your weight—Less if you have a lot of fat (fat cells have very little), more if your lean. You're muscles are about 75 percent, as is your brain and most of your organs. The total amount can fluctuate by a couple of pounds from day to day, but it's not especially important when we're talking about long-term energy balance.
The problem with energy balance is that it's complicated. But it's hard to spur people into action unless you present things as stark choices. So most public-health officials pretend that the solution to obesity is simple: "eat less, move more."
Let's walk through the actual steps of human metabolism
1. Calories in: You eat something. So far, so good.
2. Calories out: On average, about 10 percent of all food you eat will be burned up during digestion, which we call the Thermic Effect of Food, or TEF. But the total varies on the content or quality of the meal. The TEF in protein is about 25 percent. That means a quarter of the calories from protein you eat metabolizes before it can be used. For fat it's just 2 to 3 percent, and for carbohydrates it's 6 to 8 percent.
This brings me to an important Pro Tip...
If you eat less protein, you actually make it harder to lose weight. And if you replace some fat and starchy carbohydrates with protein, you should make it easier to lose weight, even if you eat the same amount of food.
3. More calories out: You also lose some energy in urine, gas, and feces.
What's left after steps 2 and 3 is called metabolized energy. The calories are dealt with below.
4. More calories out: If you were to sit in a chair for the rest of your life. Breathing. Pumping blood. Breaking down and building up your body at a cellular level. Thinking. Your brain, which is about 2 percent of your body mass, uses 20 percent of your total energy. This is called your Basal or Resting Metabolism (BMR), and it can account for as much as 70 percent of the energy you expend each day.
Your bodies lean tissue—everything that is not fat—is the driver of your basal metabolism. I always like telling my clients that your muscle is your motor which brings my to yet another Pro Tip...
The more muscle you have, all else being equal, the more calories you burn at rest. This is another way you can positivity effect your metabolism. That's why incorporating strength training into your movement routine will keep you healthy and metabolically efficient.
4. Even more calories out: Now we get to moving. These are the categories we can directly control — minus the two pro tips mentioned earlier.
We break this down into 2 categories:
Purposeful Movement (Exercise Thermogenesis or ET) like strength training, biking, running, hiking, sex, etc. For most of us this makes up roughly 8 to 10 percent of out daily energy expenditure.
Non-exercise Activity Thermogenesis (NEAT) like taking the stairs, walking to and from your car, gardening, cleaning, etc. This can make up to 20 percent of our daily energy expenditure.
Wait, was that a typo? NEAT has the potential to make up 20 percent of our daily energy expenditure? and my workouts are only 8 to 10 percent? Yes, you heard that right. Bringing me to my third and final Pro Tip.
It is an extremely important to note that your NEAT has the potential to positively affect your metabolism more than the 40-60 minutes of purposeful movement you are completing.
Many people are misinformed in thinking that slaving away for hours in the gym is the best way to burn calories, improve metabolism, and reach optimal health and body composition. I am all for working hard in the gym but I also like to use all my tools in the toolbox. And by increasing your NEAT you are making a huge change for the better. And imagine if you increased your NEAT in conjunction with your purposeful movement like strength training—Mic drop.
While researchers still don't fully understand what sets a person's metabolic rate, this information is pretty much set in stone. There are some factors of energy balance and human metabolism that we cannot control (or do not fully understand yet) but there are some ways that we can positively affect it.
1. Consume foods with a higher Thermic Effect of Food (TEF) like foods rich in protein and fiber. If you eat less protein and veggies, you actually make it harder to lose weight. And if you replace some fat and starchy carbohydrates with protein and fiber-rich vegetables, you should make it easier to lose weight, even if you eat the same amount of food.
2. Remember, your muscle is your motor. Your Basal Metabolic Rate (BMR) accounts for the largest chunk of your metabolism (up to 70%) and your lean tissue is in the drivers seat. The more muscle you have, all else being equal, the more calories you burn at rest. Incorporating strength training into your movement routine will keep you healthy and metabolically efficient.
3. Wok on improving your NEAT (Non-Exercise Activity Thermogenesis) because it has the potential to affect your metabolism more than exercise thermogenesis (ET). Or better yet, utilize both—move often, take the stairs, walk or bike when possible, and move your body in ways your enjoy.