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How Many Calories Do I Burn a Day? Understanding Your Daily Caloric Expenditure

How Many Calories Do I Burn a Day
Written by Kim Hanks

Many people wonder how many calories they burn in a day. The answer to this question depends on various factors, such as age, gender, weight, height, and activity level. Understanding how many calories you burn each day can help you make informed decisions about your diet and exercise routine.

Your basal metabolic rate (BMR), which is the number of calories your body burns at rest, accounts for the majority of the calories you burn each day. However, physical activity, digestion, and other factors also contribute to your total daily energy expenditure (TDEE). 

By calculating your TDEE, you can determine how many calories you need to consume to maintain, gain, or lose weight.

Understanding Calories

Calories are a unit of measurement used to describe the amount of energy that is stored in food. When we eat food, our bodies break it down and use the energy to fuel our daily activities. The number of calories we burn each day is determined by a variety of factors, including our age, gender, weight, height, and activity level.

To maintain our current weight, we need to balance the number of calories we consume with the number of calories we burn. If we consume more calories than we burn, we will gain weight. If we burn more calories than we consume, we will lose weight.

The number of calories we burn each day is known as our basal metabolic rate (BMR). This is the number of calories our body burns at rest, just to keep our organs functioning and maintain our body temperature. On top of our BMR, we also burn calories through physical activity and the digestion of food.

The table below shows the estimated number of calories burned per day for different age and gender groups, based on a sedentary lifestyle (i.e. little to no exercise):

Age GroupMaleFemale
18-302,4002,000
31-502,2001,800
51+2,0001,600

It’s important to note that these are just estimates, and the actual number of calories you burn each day may vary depending on your circumstances. 

If you are looking to lose weight, it’s recommended that you create a calorie deficit by consuming fewer calories than you burn each day, while still maintaining a healthy and balanced diet.

Factors Affecting Calorie Burn

The number of calories you burn in a day is influenced by several factors. Understanding these factors can help you make better lifestyle choices to achieve your fitness goals.

1. Basal Metabolic Rate (BMR)

Your BMR is the number of calories your body burns at rest to maintain basic bodily functions such as breathing, circulation, and organ function. It accounts for about 60-75% of your total daily calorie burn.

2. Physical Activity Level

The amount of physical activity you engage in affects the number of calories you burn. This includes exercise, daily activities such as walking or climbing stairs, and non-exercise activity thermogenesis (NEAT) such as fidgeting or standing.

3. Body Composition

Muscle mass burns more calories than fat mass, so people with more muscle tend to have a higher BMR and burn more calories at rest. Additionally, larger bodies require more energy to move, so people with a higher body weight tend to burn more calories during physical activity.

4. Age and Gender

As you age, your BMR decreases due to a decrease in muscle mass and hormonal changes. Men tend to have a higher BMR than women due to having more muscle mass on average.

5. Diet and Nutrition

The type and amount of food you eat can affect your metabolism and calorie burn. Eating a balanced diet that includes protein, carbohydrates, and healthy fats can help maintain a healthy metabolism and support physical activity.

In summary, the number of calories you burn in a day is influenced by your BMR, physical activity level, body composition, age and gender, and diet and nutrition. By understanding these factors, you can make lifestyle choices that support your fitness goals.

Methods to Calculate Calorie Burn

Harris-Benedict Equation

The Harris-Benedict Equation is a widely used formula to estimate daily calorie needs. It takes into account age, gender, weight, and height to calculate basal metabolic rate (BMR). BMR is the number of calories your body burns at rest. The formula then multiplies BMR by an activity factor to estimate the total daily calorie burn.

Here is the Harris-Benedict Equation for men:

BMR = 88.362 + (13.397 x weight in kg) + (4.799 x height in cm) – (5.677 x age in years)

And for women:

BMR = 447.593 + (9.247 x weight in kg) + (3.098 x height in cm) – (4.330 x age in years)

Once you have calculated BMR, you can multiply it by an activity factor to estimate total calorie burn. Here are the activity factors:

  • Sedentary (little or no exercise): BMR x 1.2
  • Lightly active (light exercise or sports 1-3 days a week): BMR x 1.375
  • Moderately active (moderate exercise or sports 3-5 days a week): BMR x 1.55
  • Very active (hard exercise or sports 6-7 days a week): BMR x 1.725
  • Extra active (very hard exercise or sports, physical job or training twice a day): BMR x 1.9

Mifflin-St Jeor Equation

The Mifflin-St Jeor Equation is another formula to estimate daily calorie needs. It is considered to be more accurate than the Harris-Benedict Equation because it takes into account lean body mass in addition to age, gender, weight, and height.

Here is the Mifflin-St Jeor Equation:

BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) + s

Where s is +5 for men and -161 for women.

Once you have calculated BMR, you can multiply it by an activity factor to estimate total calorie burn. The same activity factors as in the Harris-Benedict Equation can be used.

Katch-McArdle Formula

The Katch-McArdle Formula is a formula to estimate daily calorie needs that takes into account lean body mass. It is considered to be the most accurate formula for people who know their body fat percentage.

Here is the Katch-McArdle Formula:

BMR = 370 + (21.6 x lean body mass in kg)

Once you have calculated BMR, you can multiply it by an activity factor to estimate total calorie burn. The same activity factors as in the Harris-Benedict Equation can be used.

Calorie Burn for Different Activities

Walking

Walking is a low-impact activity that can be done almost anywhere. The number of calories burned while walking depends on various factors such as age, weight, and speed. Here is an estimate of how many calories you can burn while walking at different speeds:

  • Slow walk (2 mph): 160 calories per hour
  • Moderate walk (3 mph): 240 calories per hour
  • Brisk walk (4 mph): 320 calories per hour
  • Power walk (5 mph): 400 calories per hour

Running

Running is a high-impact activity that can help you burn a significant amount of calories. The number of calories burned while running depends on various factors such as age, weight, and intensity. Here is an estimate of how many calories you can burn while running at different speeds:

  • Jogging (5 mph): 480 calories per hour
  • Running (6 mph): 600 calories per hour
  • Running (7.5 mph): 750 calories per hour
  • Sprinting (10 mph): 1000 calories per hour

Swimming

Swimming is a low-impact activity that can provide a full-body workout. The number of calories burned while swimming depends on various factors such as stroke, intensity, and weight. Here is an estimate of how many calories you can burn while swimming for 30 minutes:

  • Freestyle (moderate): 225 calories
  • Breaststroke (moderate): 300 calories
  • Butterfly (vigorous): 375 calories
  • Backstroke (moderate): 240 calories

Cycling

Cycling is a low-impact activity that can be done indoors or outdoors. The number of calories burned while cycling depends on various factors such as speed, resistance, and weight. Here is an estimate of how many calories you can burn while cycling at different speeds:

  • Leisurely (10 mph): 240 calories per hour
  • Moderate (12 mph): 410 calories per hour
  • Vigorous (14 mph): 590 calories per hour
  • Racing (20 mph): 850 calories per hour

Role of Metabolism in Calorie Burn

Metabolism refers to the chemical processes that take place in the body to sustain life. These processes require energy, which is measured in calories. 

The amount of energy your body uses at rest is known as your basal metabolic rate (BMR). BMR accounts for approximately 60-75% of the calories you burn each day.

Several factors influence your BMR, including age, gender, body size and composition, and genetics. 

Generally, men have a higher BMR than women because they have more muscle mass. As you age, your BMR tends to decrease, which means you burn fewer calories at rest.

The other major factor that affects the number of calories you burn each day is physical activity. Exercise and physical activity increase the number of calories your body burns above your BMR. 

The amount of calories burned during physical activity depends on the type of activity, its intensity, and its duration.

In addition to BMR and physical activity, other factors can affect the number of calories you burn each day. These include:

  • Food thermogenesis: The energy required to digest, absorb, and metabolise the food you eat.
  • Non-exercise activity thermogenesis (NEAT): The energy expended during daily activities such as walking, fidgeting, and standing.
  • Hormones: Hormones such as thyroid hormones and cortisol can affect your metabolism and the number of calories you burn.

Overall, the role of metabolism in calorie burn is essential. Understanding the factors that affect your metabolism can help you make informed decisions about your diet and exercise habits.

Implications of Calorie Burn

Understanding how many calories you burn each day can have significant implications for your health and fitness goals. Here are a few key implications to consider:

Weight loss or gain

If you consume more calories than you burn, you will gain weight. Conversely, if you burn more calories than you consume, you will lose weight. Knowing your daily calorie burn can help you set realistic goals for weight loss or gain.

Physical activity

Physical activity is a major factor in calorie burn. The more active you are, the more calories you will burn. If you are trying to increase your calorie burn, increasing your physical activity is a good place to start.

Metabolism

Your metabolism is the rate at which your body burns calories at rest. This can vary depending on factors such as age, gender, and body composition. Knowing your daily calorie burn can help you understand how your metabolism affects your weight and overall health.

Nutritional needs

Your daily calorie burn can also help you determine your nutritional needs. If you are burning a lot of calories each day, you will need to consume more calories to maintain your weight and energy levels. 

Conversely, if you are burning fewer calories, you may need to consume fewer calories to avoid weight gain.

Overall, understanding your daily calorie burn can be a useful tool in achieving your health and fitness goals. By monitoring your calorie intake and physical activity, you can make informed decisions about your diet and exercise routine.

How Many Calories Do I Burn a Day? – Conclusion

In conclusion, the number of calories a person burns in a day varies depending on several factors, including age, gender, weight, height, activity level, and metabolism.

It is important to note that the number of calories burned during exercise and physical activity is just one part of the equation. A person’s basal metabolic rate (BMR) also plays a significant role in determining their daily calorie expenditure.

To maintain a healthy weight, it is recommended that individuals consume a balanced diet and engage in regular physical activity. This can help to create a calorie deficit and promote weight loss if necessary.

Overall, it is important to remember that calculating daily calorie burn is not an exact science. However, by being mindful of the factors that influence calorie expenditure and making healthy lifestyle choices, individuals can work towards achieving their weight and fitness goals.

About the author

Kim Hanks

Hanks is an author of this blog and health enthusiast who is passionate about sharing insights on health and nutrition.