How Many Calories Do You Naturally Burn in a Day? Energy Balance

Calories are the units of energy we use to measure food.

Your energy balance controls whether you maintain, gain, or lose weight.

You'll get the most from this if you already have a solid understanding of what calories are.

Let's talk about how many calories you burn in a day. We'll touch on calorie burning at rest, exercising, and during digestion.

Vintage Beam Scale with coins on left side and black background

Summary: How Many Calories Do You Naturally Burn in a Day? (TL;DR)

  • The number of calories you burn in a day depends on up to four factors - Your basal metabolism and physical activity are the two we focus on.
  • Basal metabolism is the number of calories you burn at rest - the exact amount burned is hard to pin down (see below).
  • 13 factors affect the basal metabolic rate - you have some influence over more than half of them.
  • You burn calories eating - It's variable. Anywhere from 0-30% of the energy from food is used for digestion.
  • Calories burned in a workout depends on three factors - Muscle mass, body weight, and activity.
  • Yes, your metabolism can change dramatically under drastic conditions.

Think of your body like a beam scale. One side of the scale is energy in (food). The other side of your scale is made up of what you burn in a day (energy expenditure).

In this article, we're going to talk about how you burn energy (or calories). In a separate article, we'll talk about the factors that influence the energy in side.

You can expect answers to the following questions:

  • How many calories do you burn sleeping?
  • How many calories do we burn at rest?
  • How many calories do you burn in a workout?
  • How many calories do you burn while eating?
  • Can your metabolism change suddenly?

How much walking does it take to burn 3500 calories? You might need a calculator for that.

How Many Calories Do You Naturally Burn in a Day?

The number of calories that you burn in a day depends on a large number of factors.

There are three primary ways that you burn calories:

  1. Your Basal Metabolic Rate (BMR)
  2. Physical Activity (Formal and non-formal exercise)
  3. The Thermic Effect of Food

Physical activity breaks down further into two categories:

  • Formal exercise - ex. 30 minutes of walking, cycling or, working out.
  • Non-exercise activity thermogenesis (NEAT) - calories burned while moving about throughout your day.

NEAT includes things like fidgeting, washing dishes, chewing gum, and walking your office.

There is a fourth way in which you burn calories, Adaptive thermogenesis. It's less common so we don't account for it. More on that later.

How Many Calories Do You Burn Sleeping?

The number of calories that you burning sleeping is your Basal Metabolic Rate (BMR).

Your Basal Metabolic Rate or BMR makes up the largest part of the energy you burn in a day. About two-thirds of it1.

The basal metabolism includes life-sustaining activities such as;

  • Breathing
  • Red blood cell production
  • Your heart beating throughout the day
  • Brain functions

When we measure your BMR, you're in a state of complete digestive, physical, and emotional rest. You might think of your basal metabolism as the number of calories it would take to keep you alive in a coma.

Your BMR can be affected by a large number of factors:

13 Factors Affecting Basal Metabolic Rate

Factor Effect on BMR
1. Age Lean body mass diminishes with age, slowing the BMR.
2. Height In tall, thin people, the BMR is higher.
3. Growth In children, adolescents, and pregnant women, the BMR is higher.
4. Body Composition (Gender) The more lean tissue, the higher the BMR. The more fat tissue, the lower the BMR.
5. Fever Fever raises the BMR.
6. Stresses Stresses (including many diseases and certain drugs) raise the BMR.
7. Environmental Temperature Both heat and cold raise the BMR.
8. Fasting/starvation Fasting/starvation lowers the BMR.
9. Malnutrition Malnutrition lowers the BMR.
10. Hormones (gender) The thyroid hormone thyroxine, can speed up or slow down the BMR. Premenstrual hormones slightly raise the BMR.
11. Smoking Nicotine increases energy expenditure.
12. Caffeine Caffeine increases energy expenditure.
13. Sleep BMR is lowest when sleeping.

Source: Factors that Affect the BMR1

Males are assumed to have a higher BMR than females because of the difference in the quantity of lean tissue.

The basal metabolic rate is measured directly under very specific conditions.

Tests are performed:

  • First thing in the morning, after a restful sleep.
  • Following a 12-14 hour fast.
  • Without any physical activity or emotional excitement.
  • In a comfortable setting.

BMR can vary greatly by the person due to the 13 factors listed above.

Though it won't be as accurate as a direct measure, we can use formulas to estimate your BMR. If you're slightly off, you can make adjustments over time.

Bust out those calculators.

Here's How to Calculate Your Basal Metabolic Rate (BMR):

There are two different formulas for men and women for BMR:

  • Women | BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) - 161
  • Men | BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) + 5

For example:

  • A 32-year-old, 130 lb (58.967 kg) woman standing at 5'6" (167.64 cm) might have a BMR of 1316.42.
  • A 35-year-old, 170 lb (77.1107 kg), 5'9" (175.26 cm) male might have a BMR of 1696.482.

Alternatively, you can use a BMR Calculator like this one.

Can You Do Much to Change Your Basal Metabolic Rate?

In short, kind of. Of the 13 factors affecting BMR, you have an influence over 10.

You could attempt to change your BMR by:

  • Altering body composition
  • Eating well to avoid sickness
  • Managing your stress levels
  • Changing the temperature
  • Fasting/starving (slows it)
  • Endogenous hormones (talk with your primary care physician)
  • Improving poor nutrition (speak with a registered dietitian)
  • Smoking...
  • Caffeine!
  • Improving your sleep quality

If you really want to investigate the answer to this, I suggest you reach out to a healthcare professional in your area. This article is not medical advice.

How Many Calories Do We Burn at Rest?

How many calories do you burn a day doing nothing? This is your resting metabolic rate (RMR).

Your resting metabolic rate is different from your basal metabolic rate. RMR is slightly higher than your BMR because its conditions are not as strict. RMR includes recent food intake and physical activity1.

How Many Calories Do You Burn While Eating?

Depending on the amount and type, anywhere from 0-30% of the energy from food is used in digestion.

The Thermic Effect of Feeding or TEF is the amount of energy that it takes for your body to process and store the foods that you eat. The thermic effect of food is proportionate to the size of the meal. Small frequent meals, small thermic effect. Large, infrequent meals, large thermic effect.

In general, higher protein foods are more difficult for your body to process.

Estimated thermic effect by macronutrient1:

  • Carbohydrate: 5-10%
  • Fat: 0-5%
  • Protein: 20-30%
  • Alcohol: 15-20%

For example, you might estimate that you burn 20-30 calories processing 100 calories of protein.

Try not to put too much stock into the thermic effect of food, actually, disregard it.

To quote Understanding Clinical and Normal Nutrition;

"The thermic effect of food can be ignored when estimating energy expenditure because it's contribution to total energy output is smaller than the probable errors involved in estimating overall energy intake and output." (Rolfes, Pinna, & Whitney)

A common misconception is frequent small meals ignite your metabolism, this isn't true. If you eat the same number of calories, you burn the same amount of energy digesting.

How Many Calories Do You Burn in a Workout?

The number of calories burned in a workout depends on three factors: muscle mass, body weight, and activity1.

The most variable part of the number of calories you burn a day is physical activity. You might work a job that requires you to be up and down all day. Alternatively, you could also spend half of your day trapped in a cubicle.

The amount of calories that you burn working out depends on the activity, frequency, intensity, and duration. Again, you can bust out a calculator to get an estimate here.

The table below lists the average calories burned for various activities for 30 minutes:

Calorie Burn by Exercise

Activity kCal/lb min 130 lb-person 170 lb-person 210 lb-person
Bicycling ( 13 mph) .045 175.5 229.5 283.5
Bicycling ( 15 mph) .049 191.1 249.9 308.7
Bicycling ( 17 mph) .057 222.3 290.7 359.1
Gardening .045 175.5 229.5 283.5
Running (5 mph) .061 237.9 311.1 384.3
Running (6 mph) .074 288.6 377.4 466.2
Running (7.5 mph) .094 366.6 479.4 592.2
Swimming (20 yd/min) .032 124.8 163.2 201.6
Swimming (45 yd/min) .058 226.2 295.8 365.4
Swimming (50 yd/min) .070 273 357 441
Walking (3.5 mph) .035 136.5 178.5 220.5
Walking (4.5 mph) .048 187.2 244.8 302.4
Weight Lifting (Light-mod) .024 93.6 122.4 151.2
Weight Lifting (Vigorous) .048 187.2 244.8 302.4

Source: Energy Expended on Various Activities1.

If you weigh 130 pounds, it will take you around 12.82 hours walking at 3.5 mph to burn 3500 calories.

Can Your Metabolism Change Suddenly?

Yes, your metabolism can change dramatically under drastic conditions. Adaptive thermogenesis is the additional energy that your body needs to adjust to dire situations.

For example, if you suffer third-degree burns or if you get trapped outside in the extreme cold.

This situation is the most variable by the individual. It’s another way to burn calories but is not usually taken into account.

Adaptive thermogenesis isn't the only unexpected way that calorie burn differs from your expectations. Kevin Hall, Ph.D. of the National Institutes of Health (NIH) has done a tremendous amount of research surrounded expected weight loss.

You'll be excited to learn that losing weight slows down your metabolism. This actually makes sense when you consider that smaller bodies need less energy to move.

Sources:

  1. Rolfes, S. R., Pinna, K., & Whitney, E. (2015). Energy Balance and Body Composition. In Understanding Normal and Clinical Nutrition (pp. 232-239). Stamford Place, CT: Cengage Learning.

Want to be the first to know about new content?

The best way to stay in touch is by signing up for the free newsletter. No spam, ever.