This article will explore the issue of whether to and how to use your BMR to lose weight. Anyone interested in losing fat who is using the Internet for information has no doubt come across several mysterious terms like “BMR”, “RMR”, “BMI”, “survival response”, and others. BMR is one of the big ones referenced in weight loss circles. And there are lots of issues associated with the term. Let’s explore them.

First, what is BMR?

The acronym itself stands for basal metabolic rate. Probably the most easily understood definition of BMR is what’s stated on Wikipedia. Without re-wording or paraphrasing, their definition is “bmr is the amount of daily energy expended while at rest in a neutrally temperate environment, in the post-absorptive state (meaning that the digestive system is inactive, which requires about twelve hours of fasting in humans).

The release of energy in this state is sufficient only for the functioning of the vital organs, the heart, lungs, nervous system, kidneys, liver, intestine, sex organs, muscles, and skin.”

You can put on your science hat, grab your slide rule and medical dictionary and read the full article here:

So, if you’re totally rested, non-stressed, inactive and have not eaten for 12 hours, the number of calories you burn to maintain life is your BMR.

For losing fat, it’s a good number to know but there are many factors and implications to consider before starting to use your BMR to lose weight.


  • BMR decreases with age and with the loss of lean body mass.
  • Increasing muscle mass increases BMR.
  • A very low calorie diet such as advocated by a quick weight loss diet will actually decrease BMR.
  • In the 1990’s aerobic (cardio) fitness training was shown to not increase BMR.
  • Conversely in the 1990’s research has shown anaerobic exercise (such as weightlifting) does increase BMR.
  • Illness, previously consumed food and beverages, certain prescription drugs,environmental temperature, and stress levels can affect a person’s BMR.
  • Originally, a rough estimation of BMR could be calculated by an equation using age, sex, height, and weight.
  • Studies have shown that by expressing metabolic rate based on per unit of “fat-free” or lean body weight, the values of men and women for basal metabolism are essentially the same. So to use your BMR to lose weight, should you use a formula that includes your sex as a factor?
  • The original Harris-Benedict BMR formula was created in 1919. It produced “ball-park” numbers but could not account for variations in body composition and thus made it difficult to estimate the dietary consumption any particular individual needs in order to maintain body weight. So you could not use the original BMR formula as your BMR to lose weight.
  • Then in 1990, a Dr. Mifflin introduced a new more accurate formula. His work was further enhanced by the work of a Dr. Spennewyn who constructed a formula that is currently used in many health clubs to determine daily caloric requirements. It is based on calculation of lean body mass. More studies have been performed and through the 1990’s more formulas emerged. We now have the Ketch-McAdle formula and the Cunningham formula (for the closely related RMR). And research continues to this day.


Will the real (final) BMR formula please stand up. How are you going to use your BMR to lose weight if there’s no guarantee that the numbers you’re using are accurate for your body? Certainly the formulas and methods in use today are more accurate than in the past. But there are still many unknowns.

It’s good to learn as much as you can about these things. Find out how your body operates, what its needs and realities are. But if you use formulas to calculate your BMR to lose weight, then use the numbers only as a rough guide. Include a “fudge factor” of plus or minus a few percent to your calculations. With so many variables involved, this is a realistic way to use your BMR to lose weight.


The biggest implication for using your BMR to lose weight is that we’re talking about calories here. And it comes down to computing your caloric needs (your BMR plus calories needed to fuel your activities) versus your caloric intake via the foods you consume. If you know exactly what your BMR is and if you know exactly what your daily activities require in terms of calories, then you can easily follow the golden rule of losing fat – – calories in must be less than calories out.

And in a perfect world you can find out all this stuff and use your BMR to lose weight. But it’s not a perfect world and here’s one example of where things get messed up.

Let’s say you know your BMR. You compute your caloric needs by adding in known energy expenditures for specific activities. Assume for example that your “thing” for exercise is swimming and you see a table that states swimming for some number of minutes will burn some number of calories. And let’s say that you’re a so-so swimmer. Are the exercise calorie expenditure charts accurate for your level of expertise at the activity?

An Olympic gold medalist will slice through the water much more efficiently than you while you work harder during the same timeframe and thereby burn more calories than the expert. Thus, your caloric needs based on the exercise chart may have you running a larger calorie deficit than you planned on because you had to expend more energy to accomplish the amount of work calculated for by the charts

This example applies to any physical activity you can name, from ballroom dancing to shooting hoops. An expert will use less energy than a novice. So for any activity you perform, what is YOUR true energy output and how does it relate to  use of your BMR to lose weight?

A second huge implication for using your BMR to lose weight is that by default, trying to balance your calories out to your calories in means that you need precise understanding of your actual caloric input. Inevitably this will mean needing to weigh your food servings to calculate their calorie content. This is a drag! It will make you a slave to weighed, measured portions for each meal. It strips a lot of the fun and enjoyment from eating and actually makes meals a stressful event. 

If you want to use your BMR to lose weight, that’s fine. Just be aware of the factors and implications involved. It will take a lot of determination on your part to go about losing fat in this formulaic way. But don’t despair. If you use a well balanced program of diet and exercise your body has an interesting feature that assists you in losing fat. A well balanced program will actually increase your BMR so you’ll be burning fat more quickly. So you can eat healthy with no calorie counting and still be losing weight. Check out this program for good nutrition, 90 minutes per week of exercise, NO CARDIO, and super fast fat loss.

CLICK HERE to learn about an advanced fat loss method.

In the last couple of paragraphs, a “magic” word has been introduced here on losing fat facts. Count on it being used more often in our articles. The word is BALANCE.

Your diet needs balance, not just with the foods you eat, but also how you combine them and when you eat them. And to safely lose weight, you need to balance your diet with a legitimate protocol of physical activity. And last but not least, you must balance your fluid intake according to the actual needs of your body – – drink lots of water. 

Please be sure  that before starting on any diet or exercise program, you  check with your physician first to get their concurrence and advice about your plans and goals. This is particularly important if you decide to use your BMR to lose weight because you need to get a physician’s perspective on this issue.

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