Posted by: Dr. Tyrone A. Holmes | January 27, 2011

Losing Weight with Basal Metabolic Rate: The Mifflin-St Jeor Method

Last week, I recommended determining your daily caloric needs as a means to lose weight.  I also introduced three Basal Metabolic Rate (BMR) formulas you can use to do this: the Mifflin-St Jeor method, the Katch-McCardle equation and the Harris-Benedict formula.  These formulas determine the calories you burn while at rest and then apply an activity factor to account for your daily physical activity (e.g., exercise, work at a strenuous job).  This provides you with a relatively accurate estimate of your daily caloric needs.

The Mifflin-St Jeor method uses the following formula to calculate BMR:

Male BMR = 10 × weight + 6.25 × height – 5 × age + 5
Female BMR = 10 × weight + 6.25 × height – 5 × age – 161

In these equations, weight must be in kilograms, height in centimeters and age in years.  To determine your weight in kilograms, divide your weight in pounds by 2.2. For example, if you weigh 175 lbs: 175 ÷ 2.2 = 79.54 kilograms.  To determine your height in centimeters, multiply your height in inches by 2.54.  For example, if you are 5 feet 2 inches tall: 60 inches + 2 inches = 62 inches tall x 2.54 = 157.48 centimeters.

Once you have determined your BMR, you need to multiply it by the appropriate activity factor to determine your daily caloric needs:

  • 1.200 = sedentary (little or no exercise)
  • 1.375 = light activity (light exercise/sports 1-3 days/week)
  • 1.550 = moderate activity (moderate exercise/sports 3-5 days/week)
  • 1.725 = very active (hard exercise/sports 6-7 days a week)
  • 1.900 = extra active (very hard exercise/sports and physical job)

That’s all there is to it.  Of course, if you want to avoid all of this arithmetic, simply type ‘Daily Calorie Needs’ in any search engine and you will get numerous sites that allow you to calculate your caloric needs based on your age, gender, height, weight and daily level of physical activity.

NEXT POST – January 30, 2011

Cycle Log: Intensity Phase Week 2

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Responses

  1. Say that I have calculated that my BMR is 1661. Then I multiply by the activity factor 1.375 (lightly active) to get a daily intake of 2,284 calories. I create a deficit of 1,000 calories to lose 2 pounds a week. So now my daily calorie intake goal is 1,284 calories.

    On Monday I do some cardio and burn 700 calories. I have already had my intake of 1,284 so now my net calories for the day is 584. Do I need to intake more calories to get back to a net of 1,284, or am I fine because the activity factor has already accounted for a caloric increase due to 3 workouts a week?

    Please help, I am very confused and can’t seem to find an answer.

  2. Hi Alex, thank you for your question. Simply stated, the formula has already accounted for your exercise so you do not need to take in more calories to get to a net of 1,284. More importantly, I suggest you create a deficit of 500 calories a day instead of 1,000. You will lose one pound of weight each week, which is healthier and is a more realistic expectation. Two pounds of weight loss per week will likely lead to greater loss of muscle mass and general feelings of fatigue, especially if you are exercising.

    • Hello Dr Holmes, Your answer to Alex seems to only apply if the Monday cardio is NOT beyond 1-3 days/week of light exercise(VERY vague definition). If it is beyond that then he may intake 700 more calories and be on budget. I believe I have a sedentary life and an activity factor of 1.2. Thus, any cardio can be a subtraction to my caloric tally for the day. Any problem with this? Thanks, Gbrke.

  3. Hi Gbrke, thank you for your question. The key to using the M-SJ Basal Metabolic Rate formula is the accurate selection of your activity factor. For example, if Alex is going to get more than 1-3 days/week of light exercise, he needs to use a higher activity factor (as opposed to using a lower factor and then trying to compensate with additional caloric intake). The same goes for you. If you live a sedentary lifestyle and then happen to get exercise one day, you do not need to account for that in the formula because exercise every once in a while still equates to a sedentary lifestyle! On the other hand, if you find yourself exercising more frequently, which is great, then you should account for that exercise by increasing your activity factor. I hope this helps!

  4. Can I just say what a comfort to discover a person that really understands what they are discussing on the web. You actually realize how to bring an issue to light and make it important. More people ought to look at this and understand this side of the story. I was surprised you aren’t more popular because you surely possess the gift.

  5. Hi, what about diet-induced termogenesis ? we have to add it to the end?or does not apply in this formula?

  6. its also called Thermic effect of food , thanks for your answer.


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