How many calories do you burn each day? Energy costs

as if Michael Ormsbe, Ph.D., Florida State University
Edited by Kate Findley and Angela Shoemaker, Great Courses Everyday

How many calories do you burn each day? Professor Ormsbe explains the more accurate calorie science than looking at your activity on a calorie chart.

One woman was counting calories
We use regular fitness equipment to monitor activity levels and calories burned in our daily lives. The more accurate scientific energy expenditure is done indirectly by the caloric measurement. Photo by Nestor Rizhniak / Shutterstock

Calculating energy costs

The energy balance formula consists of two parts. One is the “energy” or how many calories you consume. But how do you measure the “power outage” or energy expenditure component?

You may know the basics you need to use energy and burn calories every day, but do you know exactly how much energy you will consume in a normal day or how to measure it? Fortunately, we have scientific methods to measure the energy we consume.

Direct calorification is a very accurate way to measure your energy costs, but it is very expensive and very impractical. This method is often used by people who volunteer as research participants in large-scale clinical exercise and nutrition research.

Direct Calometer

To calculate the calorie count of foods, scientists burn them with a calorie meter and measure how much heat is given. To be clear, when measuring energy costs, they do not actually go into the combustion chamber and do not burn. Although in many ways it is the same.

For direct calorie measurement, in a well-covered chamber, it is surrounded by a certain amount of water, which is called the metabolism part, over a period of time. Let’s choose 24 hours for this example. Once you enter the chamber, do not leave it for 24 hours.

As you know, they always produce a certain amount of heat. The heat you give off in the metabolism room – from your basic metabolism requirements – heats up the room around you.

Think of a time when you were in a small room with many people. The room heats up quickly, especially if there is no airflow.

The temperature change in the neutral chamber eventually changes the temperature of the water around that chamber. Water temperature change is then used to calculate energy costs or calories burned. However, due to the ineffectiveness and cost of direct calorimetry, indirect calorimetry is often used in laboratory settings.

Indirect Calometry

Indirect caloric measurements are within ± 1% of the direct method and do not require a special component. Indirect calorimetry measures breathing – especially the oxygen you use and the carbon dioxide you emit.

How does this work? Oxygen is used during metabolism and carbon dioxide is produced. Oxygen is needed to produce ATP during rest and slow to moderate intensity exercise.

At the same time, when you break down the energy stored in your body for energy, you produce more carbon dioxide. Carbohydrates, fats, and proteins have different amounts of oxygen needed to completely break down energy, which means that different types of carbon dioxide and oxygen can be burned in your breath.

Each liter of oxygen burns an average of five calories. So, by putting it all together, we know how many calories are being burned and from which macro sources. This is done by dividing the amount of carbon dioxide produced or released by the amount of oxygen inhaled or inhaled by the respiratory rate (RER).

Differences in RER

RER values ​​are between 0.7 and 1.0. According to Professor Ormsbe, even though factors such as hyperventilation or excessive acid accumulation in the cells may slightly distort this ratio, fuel consumption is a good estimate.

For example, if you burn most carbohydrates, your RER 1.0 will be the top of the range. RER 1.0 is equivalent to five calories per liter of oxygen. This happens during strenuous physical activity.

If most fats are burned, the RER decreases by 0.7, which is about 4.7 calories per liter of oxygen. This happens during rest and during sleep.

However, many people tend to eat foods that are high in carbohydrates, proteins, and fats. As a result, people do not usually burn only carbohydrates or fats. In this case, the RER is between 0.7 and 1.0, indicating that you are using a fuel mixture of 0.85 or 4.86 calories per liter of oxygen.

Protein is rarely used in energy production such as carbohydrates and fats, so it is not specified in the RER scale. We can also use standard scientific calculations to calculate exactly how much fat or carbohydrates you make. In tomorrow’s article we will examine the implications of measuring energy costs for your health.

This article was edited daily by Kate Findley, the author of The Great Lessons, and provided daily propaganda and copy editor for the Great Courses by Angela Shoes.
Dr. Ormsbe is an associate professor in the Department of Nutrition, Nutrition and Physical Sciences at the College of Human Sciences at Florida State University and an interim director of the Institute of Sports Science and Medicine.

Michael Ormsbe is an associate professor in the Department of Nutrition, Nutrition and Physical Sciences at Florida State University College of Human Sciences, and an interim director of the Institute of Sports Science and Medicine. MS holds a Bachelor of Physiology and PhD in Bioengineering from the University of South Carolina at South Dakota State University.

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