What is Basal Metabolic Rate (BMR)?

BMR is a measurement of the level of energy, or number of calories, required to maintain the body's vital life functions at complete rest.

How is BMR measured?

Basal metabolic rate (BMR) is a portion of an individual's total energy expenditure, or number of calories required in a day. BMR is the portion of energy expended just to maintain life, such as respiration and heartbeat. It accounts for roughly 60% to 80% of an individual’s total energy expenditure. In a clinical setting BMR can be measured using indirect calorimetry, which measures the gas exchanged in oxygen and carbon dioxide. However, this is a very expensive and time consuming process. Instead, most clinicians estimate BMR using predictive equations such as the Mifflin-St. Jeor equation. The majority of online BMR calculators use another formula to measure basal metabolic rate, this formula is called the Harris Benedict equation. While both are useful for measuring BMR, the Harris-Benedict equation is usually used at a larger population level while the Mifflin-St. Jeor equation is often used in the clinical setting to measure BMR at the individual level in healthy obese and non-obese Americans.

How is BMR calculated?

The Academy of Nutrition and Dietetics recommends using the Mifflin-St. Jeor equation to calculate basal metabolic rate in both healthy obese and non-obese Americans. There are different equations for males and females, as we know that males have a slightly higher metabolic rate than females. It is important to reiterate that these equations predict the most basic caloric needs and do not factor in physical activity or metabolic stress. Therefore, total caloric needs will be higher than the calories predicted in these equations.

What is the Mifflin- St. Jeor equation for females?

10 (weight in kg) + 6.25 (height in cm) - 5 (age in years) -161.

What is the Mifflin- St. Jeor equation for males?

10 (weight in kg) + 6.25 (height in cm) - 5 (age in years) +5.

How do you increase your BMR?

Basal metabolic rate contributes to approximately 60% to 80% of our total energy expenditure. Therefore, having a higher BMR can help burn more calories. One of the best ways to increase your BMR is to increase your muscle mass. Muscle mass requires more calories at rest to maintain than fat mass. Increasing your muscle requires two things: a caloric surplus high in protein and resistance training.