BMR and BMI

Calculate Your BMR (Basal Metabolic Rate):

To estimate how many calories you should consume in order to maintain your weight, you'll need to do a little math. By using a simple formula called the Harris-Benedict principle, you can assess your basal metabolic rate -- also known as your BMR. (Then, to lose weight, you'll need to cut calories or burn extra calories and shoot for a level lower than the results you get with this formula.)

Your BMR is the amount of energy your body needs to function. We use about 60% of the calories we consume each day for basic bodily functions such as breathing. Other factors that influence your BMR are height, weight, age and sex.

Women = 655 + (4.3 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)
Men = 66 + (6.3 x weight in pounds) + (12.9 x height in inches) - (6.8 x age in years)

Calculate Activity
1. If you are sedentary (little or no exercise): BMR x 1.2
2. If you are lightly active (light exercise 1-3 days/week): BMR x 1.375
3. If you are moderately active (moderate exercise 3-5 days/week): BMR x 1.55
4. If you are very active (hard exercise 6-7 days a week): BMR x 1.725
5. If you are extra active (very hard exercise & physical job or 2x training): BMR x 1.9
Add this number to your BMR. The result of this formula will be the number of calories you can eat every day and maintain your current weight. In order to lose weight, you'll need to take in fewer calories than this result. As you lose weight, you can re-calculate the formula to assess your new BMR.

BODY MASS INDEX

Body Mass Index (BMI) is essentially a ratio of weight to height. It is a reliable indicator for weight categories which may lead to health problems such as diabetes, cancer, and heart disease. The concept of BMI was invented in the 1800's by Belgian polymath Adolphe Quetelet but its popularity can be attributed to a 1972 paper by Ancel Keys which suggested that BMI is the best proxy for body fat percentage compared to height and weight.

Here is a BMI calculator from the CDC.

BMI CATEGORY
< 18.5 : underweight

18.5 – 24.9 : normal
25.0 – 29.9 : overweight
> 30.0 : obese