Did you know that your body is burning calories right now? Even if you are lying on your bed reading this. Interesting right? I know. While we often tie a calorie burn to running, lifting weights, or sweating, the truth is that your breathing, blinking, and heartbeat requires energy every time. In essence, your body quietly burns calories all day long even when you are not working out.
For surety, we cannot undermine the major role exercising plays in staying fit and healthy, but some of your daily calorie burn comes from what your body does behind the scenes. From every breathing you make to the digestion of food, your body is performing a full-time calorie burning. Understanding how your body naturally uses energy can be a powerful tool for your weight management, improving energy levels, and making smarter health choices.
If your goal is to lose weight, maintain it, or better understand how your body works, this article will shed light on the ways you burn calories without even trying. Here, you will learn the five natural, science-backed mechanisms your body uses to burn calories everyday even without stepping foot in the gym.
1. Basal Metabolic Rate: Your Body Built-In Energy
Basal metabolic rate (BMR) is our body’s built-in energy. It is the number of calories that our body burns to perform its most basic functions while at complete rest. Examples of these basic functions are breathing, circulating blood, and cell repair. Even if we were to stay indoors all day doing nothing, our body would still burn some calories.
Research has proven that BMR accounts for 60-70% of daily calorie burn, making it the largest contributor to total energy expenditure. This is proof that most of our calorie burning happens when we are not actively exercising.
Now, we do not all share the same BMR. The BMR varies widely by several factors. They are:
Body size and composition:
People who are larger in size have a higher BMR. This is because it takes more energy to maintain a bigger body especially if that mass includes muscle. E.g, somebody who is tall and sturdy will likely have a higher BMR than a short person.
Muscle Mass:
The more muscle we have, the higher our BMR. It helps to burn calories even when we are not using it.
Age:
As we get older, BMR naturally reduces. This is because we tend to lose muscle mass and gain more fat tissue over time
Genetics:
Our inherited traits can determine how efficiently our body uses energy, stores fat, or builds muscle.
Sex:
Men generally have higher BMR than women. This is because men are known to have more lean muscle mass and larger bodies than women of the same age and weight. In reverse, women have a higher percentage of fat in their bodies, which burns fewer calories at rest. That means men are likely to burn more calories than women.
Other several factors are hormones, Environmental temperature, diet and caloric intake, pregnancy, health conditions and medications.
Healthy Tips: According to the National Academy of Sports Medicine, muscle burns approximately 3 times more calories at rest than fat. Strength training is advisable so that it can help us to boost our metabolism over time, even on days that we do nothing.
2. Thermic Effect of Food: Calories Burned During Digestion
Oftentimes, sleep gets overlooked when talking about metabolism. Sleep is actually a vital part of how our body burns calories. During sleep, our body continues to use energy to fuel brain activity, cell repair, hormone production, and organ function.
We underestimate how many calories that gets burned when asleep. Truly, we may burn fewer calories during sleep than when awake, but the body still burns an estimated 40-70 calories per hour depending on our BMR.
More importantly, quality sleep supports healthy metabolism in the long run. Having inadequate sleep can:
- Disrupt hunger-regulating hormones like leptin
- Increase cravings for sugary and highly processed foods
- Slow down your body’s ability to process glucose
- Lead to weight gain over time.
Healthy metabolism tip: Aim for 6-8 hours of regular bed-time sleep and stick to it. Avoid heavy meals and looking at screens at night.
Eating food doesn’t just fuel our body, it also burns some calories. This is a process called Thermic Effect of Food (TEF). It is the energy our body uses to digest, absorb, and process the nutrients in what we eat.
TEF represents about 10% of the caloric intake of a healthy balanced meal. It means that if we expend 1500 calories in a day, it is expected that about 150 will be burned just from eating food.
Macronutrients such as protein and complex carbs have a higher thermic effect than fats or simple carbs because our body has a harder time breaking it, making us spend more energy and burn some more calories.
Several factors affect TEF, majorly portion sizes, and macronutrient composition. Here is a breakdown of how different macronutrients affect TEF:
- Proteins burn the most calories. Its TEF is 20-30%
- Carbohydrate provides about 4 calories per gram. Its TEF is 5-15%
- Fats provide the lowest calories. Its TEF is 0-5%
In essence, this means that a high-quality protein diet like egg and tofu has a metabolic advantage over normal or low protein diets with the same amount of calories and has been proven to keep one full for a longer period of time.
Fats on the other hand, have the lowest thermic effect at approximately 5-10%. They are also the simplest to digest. That is not an excuse for excluding fats from your diet, it’s just about eating the right ones.
Good sources of fat to include in our diet are avocado, nuts, egg yolks and pumpkin seeds.
Healthy tip: To support TEF, we can try swapping our highly processed food with rich proteins, and complex carbs. This will increase our metabolism and regulate our blood sugar.
3. Non-Exercise Activity Thermogenesis (NEAT)
For every time we paced while talking on the phone, walked around the house while trying to tidy things up, or even stood in front of people to address them, we have engaged in NEAT.
NEAT is a combination of the tiny movements and activities we do throughout the day that are not formal exercise.
- Stretching during TV time
- Sweeping
- Taking the stairs
- Tidying up the room
- Gardening
Every movement taken and activities done counts.
Research proves that NEAT can vary by up to 2,000 calories a day between individuals depending on lifestyle.
Healthy metabolism tip: Increase NEAT by taking short walks during break, standing during phone calls, walking to nearby places instead of driving, doing light housework daily and many more.
4. Thermoregulation
Our body is constantly working to maintain a stable internal body temperature, despite fluctuations in the external environment. This process is called thermoregulation. Whether we are in extreme cold weather or sweating under the sun, our body adjusts to keep us balanced.
Thermoregulation systems involve the hypothalamus, sweat glands, circulatory system and skin.
The hypothalamus acts as the central control. It uses the information it receives from sensory input to produce hormones that alter body temperature. These hormones sends signals to different parts of the body so that it can respond to heat or cold in these ways:
- In cold temperatures, our body may trigger shivering to raise the body temperature. These movements involve rapid muscle contractions that burn calories to generate heat.
- In a warm environment, our body activates sweating to lower the body temperature.
Healthy metabolism tip: A brisk walk in chilly air can subtly stimulate thermogenesis.
5. Sleep and Recovery
Oftentimes, sleep gets overlooked when talking about metabolism. Sleep is actually a vital part of how our body burns calories. During sleep, our body continues to use energy to fuel brain activity, cell repair, hormone production, and organ function.
We underestimate how many calories that gets burned when asleep. Truly, we may burn fewer calories during sleep than when awake, but the body still burns an estimated 40-70 calories per hour depending on our BMR.
More importantly, quality sleep supports healthy metabolism in the long run. Having inadequate sleep can:
- Disrupt hunger-regulating hormones like leptin
- Increase cravings for sugary and highly processed foods
- Slow down your body’s ability to process glucose
- Lead to weight gain over time.
Healthy metabolism tip: Aim for 6-8 hours of regular bed-time sleep and stick to it. Avoid heavy meals and looking at screens at night.
Can I Change my Metabolism?
Even though we cannot completely alter our metabolism, we can make lifestyle changes that can influence how efficiently our body burns calories. These changes will mostly revolve around diet and exercise, focusing on building muscle mass and increasing activity levels.
Here are easy and effective ways to influence our metabolic rate:
- Eat More Protein: Protein causes the highest rise in the thermal effect of food. Eating a protein-rich meal can increase calorie burn during digestion as compared to carbs and fats. It will also help to reduce the drop in metabolism that comes with losing weight. This is because protein helps to build and maintain muscle mass.
- Increase Physical Activity: We should get engaged with strength training and intense physical activities like jogging and lifting weights. This will help to speed up our metabolism by increasing our lean muscle mass. In return, our muscle cells will burn energy even at rest.
- Get Quality Sleep: Lack of sleep affects the neuroendocrine system, which alters the whole body metabolism and disrupts key hormones which regulate hunger and appetite (leptin and ghrelin). It is also linked to a major increase in the chance of obesity. Lack of sleep may leave us often hungry and gaining unwanted weight. Getting sufficient sleep every night supports healthy hormone levels, recovery, and metabolic efficiency.
- Stay Hydrated: Drinking enough water is essential for the body to function well. Researchers have found out that drinking water may not increase metabolism but it does increase it. Learn more about hydration here.
- Manage Stress Levels: Chronic stress levels elevates cortisol, a hormone that can slow metabolism, increase appetite for food intake, and promote fat storage. Although a 2020 Study did not find any conclusive evidence linking resting metabolic rate and stress. We can conclude that stress has an indirect effect by affecting eating patterns and sleep, both of which can alter the rate of metabolism.
- Seek Treatment for Hypothyroidism: Having a low level of thyroid hormone may likely result in a slower metabolism at rest and having an increased risk of weight gain. Seeking the right help from a professional can help speed up metabolic rate and reduce the risk of complications linked to it.
Should We Focus on our Metabolic Rate?
Talking about metabolism and calorie burn is fun, but it should be viewed from a balanced perspective. Obsessing over metabolism won’t magically burn off fat. Instead, we should support our metabolic rate by making smarter choices for our weight management, energy levels and overall wellbeing.
Dr. Griebeler once said “Counting calories burned through your metabolic rate is not where we should be aiming”. “Instead, focus on physical activity, managing your stress, sleeping well and eating right. You will find your balance there.”
The bottom line is that we can’t take shortcuts. We have to align our habits like (movement and diet) with how our body naturally burns calories everyday to keep fit.