Mathematical Nutrition Part 2 - BMR

**BJJones37** · 08-07-2011, 06:08 AM

It is interesting to note that we often refer to "fattening" foods when in fact no foods are fattening, or all foods are fattening. It is not even the quantity of food that produces fat, it is the calories that are consumed in excess of what is burned. I have heard most of my life that in order to lose weight one must reduce the amount of food consumed. I have since discovered that I can actually increase the amount of food I eat and still lose weight. It is not about food, it is about calories.

It is necessary to know one's BMR - Basic Metabolic Rate - in order to have a good grasp of how many calories per day should be consumed. You can consider the BMR to the the number of calories you would burn if you were to sleep for 24 hours. It is the number of calories required to maintain your metabolism at a stable rate with no loss and no gain. If you consume only the number of calories in your BMR, you will lose weight - unless you sleep for 24 hours. Even the act of eating consumes some calories (what a comfortung thought). You should NEVER eat less than your BMR for a prolonged period. That can have serious consequences to your health. Instead, you should simply increase your activity levels to burn more calories. You can calculate your own BMR for both your current weight and your target weight. I like to use a spreadsheet to do this. Here are two common methods used.

BMR - minimum amount of energy required when resting
Mifflin BMR
Male: BMR = 10×weight(lbs)/2.2 + 6.25×height(inch)*2.54 - 5×age + 5
Female: BMR = 10×weight(lbs)/2.2 + 6.25×height(inch)*2.54 - 5×age - 161

Harris BMR
Male: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) - ( 6.8 x age in years )
Female: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) - ( 4.7 x age in years )

A couch potato such as myself would add an additional 20% to my BMR to determine how many calories I would need for the day. An Olympic athlete in training would probably eat twice his BMR each day. You base your actual calorie consumption on you level of activity.

To determine your total daily calorie needs, now multiply your BMR by the appropriate activity factor

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 Moderately Active (moderate exercise/sports 3-5 days/week)
Calorie-Calculation = BMR X 1.55

If you are Very Active = BMR X 1.725 (hard exercise/sports 6-7 days/week)
Calorie-Calculation = BMR X 1.725

If you are Extra Active (very hard daily exercise/sports & physical job or 2X day training)
Calorie-Calculation = BMR X 1.9

Now do not think that you have to exercise "Real Hard" in order to burn calories. If you do 100 situps - pretty tough stuff - you only burn about 20 calories. I like to take a walk in the mornings with my wife and enjoy the pleasure of her company. We walk about three miles and chat and in the process burn about 230 calories without even trying. Takes less than an hour. If you weigh more than I do (about 143 lbs) then you will be burning even more calories on the same walk!

Next article will be about how to lose weight without going hungry - or Eat more and Weigh less. But it will be called "Fiber Ratio".

*** The attachment contains an Excel spreadsheet with the equations to make it easy to calculate BMR and BMI for you. Just enter the Blue values for yourself.