Tip: How to figure out your BMR and Calorie Requirements
Posted on March 17th, 2009 in Tips, Weight Control | 4 Comments »
If you want to lose weight, gain weight or simply maintain your weight, you need to figure out how many calories your body needs on a daily basis. You can get a pretty good idea by getting your BMR or Basal Metabolic Rate and adding the amount of calories you expend beyond that. Basically BMR is the number of you would burn if say, you laid in bed all day long. To get an accurate figure would require a lab. However, you can get a pretty good estimate using a simple equation. We will get to that in a moment.
To find out how many calories we expend beyond our BMR we need to find our activity level using the Harris Benedict Formula.
Ok, so here we go. To find out how many calories you burn, do the following…
Step 1 – Figure out your BMR
English BMR Formula
Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) – ( 4.7 x age in years )
Men: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) – ( 6.8 x age in year )
Metric BMR Formula
Women: BMR = 655 + ( 9.6 x weight in kilos ) + ( 1.8 x height in cm ) – ( 4.7 x age in years )
Men: BMR = 66 + ( 13.7 x weight in kilos ) + ( 5 x height in cm ) – ( 6.8 x age in years )
Step 2 – Figure out your activity factor and add it to your BMR
We will use the Harris Benedict Formula to determine your total caloric requirements
- If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2
- If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375
- If you are moderatetely active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55
- If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725
- If you are extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9
Example
Ok, so let's figure out John Doe's total caloric requirements. Joe, 35 years old, is a 6 ft, 175 pound male. While Joe has a desk job he works out regularly using P90X. So using the BMR formula we get this…
Step 1 – Get Joe's BMR
66 + ( 6.23 x 175 lbs ) + ( 12.7 x 72 inches ) – ( 6.8 x 35 years old)
Simplified… 66 + 1090.25 +914.4 – 238 = 1832.65
BMR = 2308.65
Step 2 – Add Joe's activity level to his BMR
According the Harris Benedict formula (see above), Joe's activity factor is 1.725 (P90X is an intense 6 day a week workout program). So…
2308.65 x 1.725 = 3161.3
Joe burns over 3000 calories a day!
So if Joe wants to lose weight, he could reduce his caloric intake by about 500. So he could eat around 2661 calories a day. Over a period of 7 days he could shave 3500 calories (7 x 500). That is roughly a pound a week.
4 Responses
Great post!
I was thinking about writing about this sometime soon. Figuring out these formulas is helpful in setting goals. Lately the theory just doesn’t seem to be working. I have hit a plateau and haven’t lost any weight for a month. Very frustrating.
According to the formula I’m burning 2650 a day and according to my Fitday program, I’m consuming 2003 calories a day. The carbs-protein-fat mix is close, not right on. I haven’t seen much changes in measurements.
I was really planning on staying strictly with just the workouts, but if I don’t see some changes soon, I’m going to either drop the Kenpo and Plyo and hit the stationary bike instead for cardio.
Mark, thanks for the comments.
Yes, I know what you mean. Theory-wise we should be shedding weight. As far as the scale goes I seem to be at a plateau with my weight too.
I have been working out very hard and have been on top of my calories. So I measured my body fat. The great news is that I lost a couple percentage points of BF so I know that my fat loss is being offset by my lean muscle gains. That makes sense because my arms are becoming more defined and vascular. On the top banner of my website I placed a photo of my bicep. After I took the picture I was pleasantly surprised to see the definition.
The other thing about this whole thing is that if I don’t keep my calories high enough, my metabolism slows down. It is just a balancing act that I need to watch.
Hey
Looks like there’s a mistake in your maths. You went:
66 + 1090.25 +914.4 + 238 = 2308.65
Should have been:
Simplified… 66 + 1090.25 +914.4 – 238 = 1832.65
1832.65 * 1.725 = 3161 calories per day
Colin…
Thanks for the correction. Looks like I added the 238 instead subtracting it! I made the correction to my post.
Poor Joe, I cut his calories!!!