Have you ever wondered how many calories you burn each day? The Harris-Benedict formula can help you figure out the answer to this question. It not only helps you calculate your individual basal metabolic rate (BMR), but it also shows you your daily calorie requirements.
The Harris-Benedict formula or Harris-Benedict equation was first published back in . It was revisited in 1984 and again in 1990 to improve the accuracy. In its basic form, you multiply your BMR by your daily activity level to get the number of calories you need to consume each day to maintain your weight.
How do you get these numbers?
To calculate your BMR, you’ll use your sex, age, and weight. The original formulas for calculating this number are as follows, using pounds for weight, inches for height, and years for age.
- 66 + (6.2 x weight) + (12.7 x height) - (6.76 x age) = BMR for men
- 655.1 + (4.35 x weight) + (4.7 x height) - (4.7 x age) = BMR for women
A 40-year-old, 150 pound, 5 foot 6-inch-tall woman, for example, would be 655.1 + (4.35 x 150) + (4.7 x 66) - (4.7x40) = 1,429.7.
A 40-year-old, 180 pound, 6-foot-tall man would be 66 + (6.2 x 180) + (12.7 x 72) - (6.76 x 40) = 1,829.8.
From there, you must figure out your activity level. The activity level number is defined as:
- 1.2: sedentary (little to no exercise)
- 1.375: lightly active (light exercise 1-3 days per week)
- 1.55: moderately active (moderate exercise 3-5 days per week)
- 1.725: very active (hard exercise 6-7 days per week)
- 1.9: extra active (very hard exercise/training or physical job)
For example, let’s say a woman is a postal worker and walks all day. Her activity level would be set to 1.9. Now let’s say a man works at a desk and walks for exercise several times a week. His activity level would be set to 1.55.
Putting everything together, the Harris-Benedict equation is: BMR x activity level = calories to maintain weight
The 150-pound woman who is “extra active:”
- 1429.7 (BMR) x 1.9 (activity level) = 2,716 (calories/day to maintain current weight)
The 180-pound man who is “moderately active:”
- 1829.8 (BMR) x 1.55 (activity level) = 2,836 (calories/day to maintain current weight)
To make this whole equation even easier, there are online calculators that do the math for you.
As you can see in the above examples, activity level has a lot to do with your results. And you may think you need to exercise hard to burn calories throughout the day. That’s true, but you also burn a good number of calories while going about your normal daily tasks. How much you’ll burn has to do with how much you weigh.
Here’s how much a 155 pound person burns doing the following tasks for 30 minutes.
|grocery shopping (with cart)||130|
|light office work||56|
|playing with kids||149|
|sitting in meetings||60|
|standing in line||47|
|walking (3.5 mph)||149|
The answer to the question whether men and women burn calories differently is “Yes.” To calculate your individual basal metabolic rate, you must take three factors into account: your age, sex, and weight/body composition.
How does sex fit into the equation?
Men generally have less body fat than women. This means they often have more muscle mass than women — even than women who are the same age and weight. More muscle means more calorie burn while at rest. So, generally speaking, men do burn more calories than women overall.
Knowing your daily caloric requirement to maintain your weight can also help you lose weight. It takes burning 3,500 calories to lose a pound. So, if your daily caloric requirement to maintain your weight is 2,500 calories, you’ll need to either eat less or exercise more. How much depends on how much weight you want to lose and how quickly you want to lose it.
Experts recommend aiming to lose just a pound or two per week for the most sustainable weight loss. To lower your calories by 3,500 to 7,000 a week, you’ll need to shoot for a 500 to 1,000 calorie deficit each day. You can do this all through diet, exercise, or a combination of the two.
Losing weight isn’t always as simple as plugging numbers into a calculator. Your best bet is to eat well, exercise most days of the week, and keep at it for the long run.
- keeping a food diary to see what you eat in a day and to identify problem areas in your diet
- passing on processed, high-calorie, low-nutrition foods, like candy, cookies, chips, etc.
- choosing lower calorie options for your favorite high-calorie foods like skim milk instead of whole milk, air-popped popcorn instead of chips, and thin crust pizza instead of thick crust
- slimming down your portion sizes so you’re truly eating just one portion of whatever food is on your plate
- reading labels to learn what’s really in the food that you’re consuming
- putting food on a plate versus eating it straight from the bag
- making small, sustainable changes instead of favoring a crash diet