Understanding How Many Calories Do You Naturally Burn in a Day?

October 6, 2025 •

4 min read

Your body burns up to 70% of its daily calories simply by performing basic functions like breathing and pumping blood. Understanding how many calories do you naturally burn in a day is key to managing your weight and optimizing your nutrition plan effectively. This expenditure, known as your metabolism, is influenced by numerous factors beyond just exercise.

Quick Summary

The number of calories your body naturally burns each day depends on your basal metabolic rate (BMR), the thermic effect of food (TEF), and physical activity. Factors like age, gender, muscle mass, sleep, and stress also play significant roles in determining your total daily energy expenditure (TDEE).

Key Points

Total Daily Energy Expenditure (TDEE) is personalized: The number of calories you burn is unique to you and influenced by your basal metabolic rate (BMR), physical activity (AEE), and the thermic effect of food (TEF).
BMR is your biggest calorie burner: Your Basal Metabolic Rate (BMR) accounts for 60-70% of your daily calorie expenditure, sustaining basic bodily functions at rest.
Muscle boosts your metabolism: Building lean muscle mass through strength training increases your BMR, helping you burn more calories even when you are not exercising.
NEAT adds up: Non-Exercise Activity Thermogenesis (NEAT), which includes all your non-workout movement, can contribute significantly to your daily calorie burn and is a key area for increase.
Lifestyle factors matter: Sleep, stress, hormones, and genetics all play a significant role in your metabolic rate and weight management success.
Protein has a high thermic effect: Your body uses more energy to digest protein than it does fat or carbs, making a protein-rich diet a way to slightly boost your metabolic rate.

The Components of Your Daily Calorie Burn

Your total daily energy expenditure (TDEE) is a measure of the total number of calories your body burns in a 24-hour period. It is comprised of three main components: your Basal Metabolic Rate (BMR), the Thermic Effect of Food (TEF), and Activity Energy Expenditure (AEE). By understanding each part, you can gain a more accurate picture of your metabolic health.

Basal Metabolic Rate (BMR)

Your BMR accounts for the largest portion of your daily energy use, typically 60-70%. This is the energy your body needs to perform life-sustaining functions while at complete rest, including breathing, circulating blood, and maintaining body temperature. A higher BMR means you burn more calories without any conscious effort. Factors that influence your BMR include age, gender, weight, height, and body composition. As you get older, your BMR tends to slow down, largely due to a loss of muscle mass.

Thermic Effect of Food (TEF)

TEF is the energy your body uses to digest, absorb, and process the nutrients from the food you eat. This component typically makes up about 10% of your TDEE. The amount of energy burned during digestion varies depending on the macronutrient composition of your meal. Protein has the highest thermic effect (20–30%), followed by carbohydrates (5–10%), and fats have the lowest (0–3%). Eating a diet rich in protein and whole foods can slightly increase your overall calorie burn.

Activity Energy Expenditure (AEE)

AEE covers all the calories you burn through physical movement and accounts for 15-30% of your TDEE. This can be further broken down into two parts:

Exercise Activity Thermogenesis (EAT): The calories burned during structured, intentional exercise, such as running, swimming, or weightlifting. The intensity and duration of your workouts significantly impact how many calories you burn through EAT.
Non-Exercise Activity Thermogenesis (NEAT): This is the energy expended for everything you do that is not sleeping, eating, or sports-like exercise. This includes walking, fidgeting, standing, and performing household chores. For some, NEAT can be a major contributor to their daily calorie burn and can explain significant variances in energy expenditure between individuals.

Key Factors Influencing Your Natural Burn

Numerous individual factors impact the rate at which your body burns calories. While some are genetic, others are controllable.

Body Composition: Lean muscle mass burns more calories at rest than fat tissue. A person with more muscle will have a higher BMR than someone of the same weight with more fat.
Age and Gender: BMR decreases with age due to muscle loss and other physiological changes. Men generally have a higher metabolic rate than women because they typically have more muscle mass and larger body frames.
Genetics: Your genetic makeup plays a role in determining your metabolic rate, how your body stores fat, and how you respond to diet and exercise.
Hormonal Health: Hormones like thyroid hormone, insulin, cortisol (the stress hormone), leptin (the fullness hormone), and ghrelin (the hunger hormone) all influence your metabolism and appetite.
Sleep and Stress: Lack of sleep and high stress levels can slow down your metabolism, disrupt hunger hormones, and increase fat storage, particularly around the abdomen.

Practical Ways to Increase Your Natural Calorie Burn

Boosting your metabolism doesn't require extreme measures. Small, consistent changes can make a significant difference over time.

Build Lean Muscle: Incorporate strength training into your routine. Muscle tissue is more metabolically active than fat, meaning it burns more calories even at rest.
Increase NEAT: Find ways to be more active throughout your day. Stand up while taking phone calls, take the stairs instead of the elevator, or park further away from your destination.
Prioritize Protein: Due to its high thermic effect, including adequate protein in your diet can increase the calories your body burns through digestion.
Don't Skip Meals: Eating too few calories can cause your metabolism to slow down as your body tries to conserve energy.
Stay Hydrated: Drinking enough water is crucial for optimal metabolic function. Some studies suggest drinking cold water can increase calorie burn as your body works to warm it up.

BMR vs. TDEE Comparison Table


Feature	Basal Metabolic Rate (BMR)	Total Daily Energy Expenditure (TDEE)
Definition	The minimum number of calories your body burns at complete rest.	The total number of calories your body burns in a day, including all activity.
Included Activities	Essential bodily functions (breathing, circulation) in a fasting and rested state.	BMR + Thermic Effect of Food + all physical activity (exercise and NEAT).
Typical % of TDEE	60–70% for most sedentary individuals.	100% (the full energy expenditure for a day).
Usage for Goals	Provides a baseline number of calories needed to exist. You should never eat below this amount for a prolonged period.	Provides an estimate of calories needed to maintain weight. Adjust this number to lose, maintain, or gain weight.

Conclusion

While the exact number of calories you naturally burn in a day is impossible to pin down perfectly, understanding the components of your TDEE provides a powerful framework for weight management. Your body's resting metabolism (BMR), digestive process (TEF), and daily movement (AEE) all contribute to your total calorie burn. By focusing on factors like building muscle mass, staying active through NEAT, and managing lifestyle elements like stress and sleep, you can influence your metabolic rate. Instead of getting hung up on a precise number, focus on healthy habits that positively impact your overall energy expenditure and support long-term well-being.

Frequently Asked Questions

BMR (Basal Metabolic Rate) is the minimum amount of calories your body needs to sustain essential functions at rest, such as breathing and circulation. TDEE (Total Daily Energy Expenditure) is your BMR plus the calories burned from all your daily activities, including exercise and non-exercise movement.

To calculate your TDEE, you first need to estimate your BMR using a formula like the Harris-Benedict equation, which factors in your age, gender, weight, and height. You then multiply your BMR by an activity factor based on your typical weekly exercise level. Many online calculators automate this process.

Yes, metabolism generally slows with age. This is primarily due to a natural loss of lean muscle mass. However, you can mitigate this decline by incorporating regular strength and resistance training to build or maintain muscle tissue.

NEAT stands for Non-Exercise Activity Thermogenesis. It's the energy you burn from all physical activity outside of planned exercise, such as walking, cleaning, and even fidgeting. Increasing your NEAT throughout the day, like taking the stairs or standing more, can significantly boost your total daily calorie burn.

Poor sleep and high stress levels can negatively impact your metabolism. Lack of sleep disrupts hormones that regulate appetite (leptin and ghrelin) and can slow your metabolic rate. Stress triggers the release of cortisol, which can increase cravings for high-calorie foods and promote fat storage.

While no single food acts as a magic bullet for weight loss, some foods require more energy to digest than others. Protein, for instance, has a higher thermic effect than fats or carbs, meaning your body burns more calories processing it. Spicy foods and green tea may offer a small, temporary boost.

Muscle mass is one of the strongest determinants of your BMR. Because muscle tissue is more metabolically active than fat, building and maintaining it is a highly effective way to increase your natural calorie-burning potential, even at rest.