Caloric Intake to Lose Weight. Formulas of Mifflin-St. Jeor and Harris-Benedict





Activity Level

Metric Units

Estimation formula

Maintain weight

Weight loss

Extreme weight loss

Extreme weight lossWeight lossMaintain weight

Many people would like to be fit nowadays. Some of them clearly understand that a good shape may be the result of long-hours’ work only. Others believe that what you need to look slim and attractive is just dieting. One of the most important factors which should be considered by both groups is our basal metabolic rate.

You know, chemical processes go on continuously inside our body to keep us alive and our organs functioning in a proper way. The minimum amount of energy our body needs to perform all these functions is called the basal metabolic rate (BMR).

Your metabolism may be partly determined by your genes, although this isn’t for sure and hasn’t been proven with 100 per cent accuracy. The question how to calculate metabolic rate could be especially essential for those people who struggle to lose weight and who believe that slow metabolism is often to be blamed for them being overweight or even obese.

Sounds strange, but some scientific research shows that overweight people have a faster metabolism than thinner people. That’s because larger bodies require more energy to carry out basic bodily functions. Nevertheless, we shall not deny the importance of metabolism in our bodies.

In fact, inactive calories’ calculations could give you good grounds for thinking. Do you need to change anything in your nutrition plan? Is the fact that you are becoming overweight connected with your sedentary lifestyle? Do you tend to eat more calories than you burn? It may turn out so that the reason for you to put on weight isn’t your slow metabolism, it’s because you’re eating and drinking more calories than you’re burning. When you are ready to accept that indisputable fact, you have the key to success!

Caloric Intake to Lose Weight

Loosing, gaining, or maintaining weight is not a myth! You could do it if you properly estimate your basal metabolic rate and your daily activity plan! Activity is a keyword here because muscle cells require more energy to maintain than fat cells, so people with more muscle than fat tend to have a faster metabolism.

The basal metabolic rate calculators actually bmr at rest calculator which counts the amount of energy that is expended at rest in a neutral environment after the digestive system has been inactive for about 12 hours. It is the rate of a person’s metabolism when waking in the morning after “fasting” during sleep.

The best predictor of your basal metabolic rate is your lean body mass.  Maintenance of lean body mass is possible if a person does physical exercises regularly. Expending extra calories through increased physical activity is the most sensible way to increase metabolism.

But when a person keeps a diet, BMR slows down to conserve energy and protect vital organs. A regimen of reasonable dieting with increased exercise maintains or increases BMR and promotes weight loss and weight maintenance. In such a case it mostly depends on calories and caloric balance.

BMR calculator (or BMR at rest calculator) gives some basic information about our body, but to be more informed and be ready to transform our body and achieve the ideal result we dream about we need to take more parameters into account. One of the most important things in such a case is your lifestyle.

Some people have a sedentary lifestyle, do little or no exercises, some do exercises either once or twice a week or unable to do them regularly, but some other people have very intensive and strenuous exercises daily or have a physically demanding job. Surely, the more calories you burn the more remarkable may be the effect if you would like to influence your metabolic rate and change your body.

The Harris-Benedict Equation and The Mifflin-St Jeor Equation are aimed at assisting people to assess their lifestyle, to understand how to calculate BMR  depending on their lifestyle and, the last but not least, how to change their metabolism and be fit and happy!

The Harris-Benedict Equation was one of the earliest equations introduced. It was revised in 1984 to be more accurate and was used up until 1990, when the Mifflin-St Jeor Equation was introduced. In fact, the Mifflin-St Jeor Equation turned to be more accurate than the revised Harris-Benedict Equation. Why were these equations necessary? Because estimating daily calorie requirements is always challenging, especially if you are not a nutrition specialist, a coach or a cook. Even the best calculators cannot determine metabolic rate for every male or female absolutely correctly.

BMR is a measure of only the most basic functions (effectively the same as if you rested in bed the whole day). Once BMR has been estimated, various activity factors shall be also analyzed. One important point is that one individual may burn 100 calories on a 10 minute run – another individual may burn 110 calories.

Mifflin St. Jeor Equation Calculator

Mifflin – St Jeor Formula (Mifflin-St Jeor Equation) is considered to be more accurate than Harris-Benedict Equation nowadays.


10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) + 5


10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) – 161.

The Mifflin-St Jeor Equation calculates your basal metabolic rate (BMR), and its results are based on an estimated average. The basal metabolic rate is the amount of energy expended per day at rest.

Directions how to use the calculator:

  • Select your sex.
  • Enter in your weight and select lbs or kgs.
  • Enter in your height and select inches or cm.
  • Enter in your age. You now have your BMR.

Basic Activity Factor

  • 1.2: If you are sedentary (little or no exercise) = BMR x 1.2
  • 1.375: If you are lightly active (light exercise/sports 1-3 days/week) = BMR x 1.375
  • 1.55: If you are moderately active (moderate exercise/sports 3-5 days/week) = BMR x 1.55
  • 1.725: If you are very active (hard exercise/sports 6-7 days a week) = BMR x 1.725
  • 1.9: If you are extra active (very hard exercise/sports & physical job or 2x training) = BMR x 1.9
Formulas of Mifflin-St. Jeor and Harris-Benedict

Mifflin St Jeor calculator with activity factor surely gets priority when people would like to estimate calories for weight loss. After calculating the BMR, exercise is factored in. Depending on the exercise level chosen, the BMR will be multiplied by anything from 1.2 to 1.9. This provides us with calories intake, that is the amount of calories a person could consume each day and neither lose or gain weight. To get the fat loss the nutritional value (calories’ amount) shall be 20 per cent lower than the initial amount.

The extreme fat loss figure has 40% subtracted. However – there is a ‘rock bottom’ figure that equates to 8 calories per pound of body weight – the extreme fat loss will never be less than this amount. This has been put into the calculator as a failsafe to prevent users from embarking on highly-restricted diets. Such diets need medical care, advice, and monitoring. It is also not advised to drastically reduce calories, but rather do so gradually or by a maximum of 500 calories per day.

Harris-Benedict Equation Calculator

Some people and nutrition specialists ask why use Harris-Benedict equation if Mifflin St Jeor equation is recognized to be more perfect. First, that  Harris-Benedict formula may be more suitable for the client’s goal, it is easy to assess caloric requirements with the help of Harris-Benedict equation calculator. Second, this tool was originally aimed for healthy individuals of both genders. You know, Harris-Benedict Formula was created in 1919, and due to changing lifestyles, it tends to overstate calorie needs by 5%. The results tend to be skewed towards both obese and young people.


66.5 + (13.75 × weight in kg) + (5.003 × height in cm) – (6.775 × age in years)


655.1 + (9.563 × weight in kg) + (1.85 × height in cm) – (4.676 × age in years)

Was this information useful?

Legal Notice

This article is aimed at providing helpful and informative material on the subject only. It is intended as a reference volume only, not as a medical manual. The information given here is designed to help you make informed decisions about your health. It is not intended as a substitute for any treatment that may be prescribed by your doctor or any recommendations that may be given by a medical specialist. If you suspect that you have some medical problem, we urge you to seek competent medical assistance.

Before starting any weight-loss plan or beginning or modifying any exercise program, always consult with your doctor or any health professional and make sure that the changes are right for you.

The author and publisher of the article specifically disclaim all responsibility for any liability, loss, or risk, personal or otherwise, that is incurred as a consequence, directly or indirectly, of the use and application of any content of that site, including the results of the calculations.

(Visited 76 times, 76 visits today)
Spread the love

Your comment

Your email address will not be published. Required fields are marked *

© 2020 Health Body Calculators · Copyright © All rights reserved
Proudly powered by WordPress