Have you ever wondered how dietitians estimate how many calories their clients should eat in a day? While the science is far from exact, several useful calculations can help determine how many calories you should eat for weight loss, gain, or maintenance.
Part of the calculation determines your resting metabolic rate (RMR), which is how many calories your body burns while at rest. You can calculate your RMR to see how many calories your body needs to perform basic functions like breathing and circulation. To properly track this most seek assistance and search for RMR testing near me. The amount of activity you do also determines how many calories you may need each day. Read on to learn some tips and tricks for estimating your energy needs.
What Is Metabolism and Metabolic Rate?
Metabolism refers to all of the reactions that occur within each cell of the body and provide the body with energy.1 Metabolism is how our cells change the food we eat into energy for our daily functioning—from breathing to circulation to chewing to walking.
Each food you consume contains nutrients, such as protein, vitamins, and minerals. Your body absorbs the nutrients and converts them into units of heat—or calories. The energy—the calories—that are provided by the food are either used right away or stored for your body to use later. Extra calories are usually stored as fat.
Metabolic rate measures the energy we use in a given time period.2 It can be affected by age, diet, sex, race, disease, and activity level.1
What Is Resting Metabolic Rate?
If it’s being measured clinically in a lab, BMR is assessed first in the morning. It is done when a patient is at rest after an overnight fast and has had no exercise for the previous 24 hours.4 RMR is measured after at least 15 minutes of rest with few other restrictions and does not need to be measured before getting out of bed.
If you are not measuring BMR or RMR in a lab setting and are using a simple calculation instead, the time of day doesn’t matter. Studies show that RMR may be a better indicator of daily energy needs than BMR.4 Once you measure your RMR, the answer will give you the approximate number of calories your body burns daily while at rest.
How to Calculate RMR
There are many ways to calculate RMR and BMR. The simplest is by plugging numbers into a calculation that takes your height, weight, age, and gender into account, but the accuracy of this method is questionable.
A lab-based test called indirect calorimetry is the most reliable method to measure RMR, but this method is expensive and time-consuming.
Calculate RMR in a Lab
Some medical facilities offer indirect calorimetry to provide you with a metabolic rate that’s more reliable than using a calculation. The test is non-invasive and usually takes about an hour.
For the test, you will wear a mask for a short period of time (around 15 minutes) while resting. The mask measures the exchange of gasses to determine the number of calories you burn when your body is at complete rest.8 The test is most often used in critically ill patients to determine their nutritional needs, but some non-medical settings (like gyms) may also offer it.