A calorie is just a measure of energy. We require a lot of energy just to stay alive. Anytime we move any muscle, we require even more energy. It is no different than the energy that your car requires to drive down the road. If your car is out of gas, it won’t be going anywhere. Gasoline for your car contains almost 31,000 calories of food energy per gallon, which is the same energy as in about 55 Big Mac hamburgers. Cars weigh thousands of pounds, so it takes a lot of energy to move them down the road.
The total energy that your body requires while you are lying still is called your resting metabolic rate (RMR). (It is also called the basal metabolic rate or BMR). Your resting metabolic rate mostly depends upon your physical size. The larger our bodies are, the more energy we will need even if we are lying around all day.
Scientists created a formula to calculate the resting metabolic rate based on experiments done almost 100 years ago. This is called the Harris-Benedict equation:
For Women: BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)
For Men: BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years)
You can use a calculator and calculate your own resting metabolic rate. Another easy way to find your own resting metabolic rate is to do an Internet search for “BMR calculator” and just plug in your weight, height and age. For example, a 40 year-old woman who is 5 feet 4 inches (64 inches) tall and weighs 140 pounds has a resting metabolic rate of 1377 calories per day. If she weighed 200 pounds, her resting metabolic rate would be 1638 calories per day.
If a completely sedentary person consistently eats 500 calories more than she needs to maintain her current body weight, she will gain weight until her new resting metabolic rate matches how many calories she eats each day. For example a 40 year-old 5 foot 4 inch woman weighing 140 pounds who does nothing but lie around in bed all day needs 1377 calories every day to maintain her weight. If she instead eats 1877 calories every day, she will gain weight until her new resting metabolic rate equals 1877 calories, which happens when she weighs 255 pounds.
Unless you never get out of bed, the amount of calories you use in a day is considerably more than your resting metabolic rate. Any time we move any muscle we use up more energy than our resting metabolic rate. If you are sitting at a desk doing office work such as writing or typing, you are using calories about 1 1/2 times as quickly as your resting metabolic rate. When you are standing and moving around doing light housework your body is burning calories about 2 1/2 times your RMR. Walking slowly causes you to use about 2 1/2 times your RMR, but walking quickly for exercise uses about 3 1/2 times your RMR. If instead of walking you decide to jog, cross country ski, or backpack, you will use energy at a rate of about 7 to 9 times your RMR.
For example, a 40 year-old 5 foot 4 inch woman weighing 200 pounds has a resting metabolic rate of 1638 calories per day, or 68 calories every hour. So when she is sleeping or reclining watching television, that is how many calories her body requires. If she has a desk job, she will burn calories at a rate of 1.5 times her RMR while at work, or about 102 calories per hour. While she is walking around the house and doing light housework, she will burn calories at a rate of about 2.5 times her RMR, or about 170 calories per hour. If she decides she needs more exercise and goes out jogging, she will use calories at a rate of about 544 calories per hour. This means that if she spends an hour jogging instead of sitting at her desk, she will use 442 calories more than she would have if she had not gone jogging. For every hour she spends walking instead of sitting, she is burning an extra 68 calories.
The total energy that your body requires while you are lying still is called your resting metabolic rate (RMR). (It is also called the basal metabolic rate or BMR). Your resting metabolic rate mostly depends upon your physical size. The larger our bodies are, the more energy we will need even if we are lying around all day.
Scientists created a formula to calculate the resting metabolic rate based on experiments done almost 100 years ago. This is called the Harris-Benedict equation:
For Women: BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)
For Men: BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years)
You can use a calculator and calculate your own resting metabolic rate. Another easy way to find your own resting metabolic rate is to do an Internet search for “BMR calculator” and just plug in your weight, height and age. For example, a 40 year-old woman who is 5 feet 4 inches (64 inches) tall and weighs 140 pounds has a resting metabolic rate of 1377 calories per day. If she weighed 200 pounds, her resting metabolic rate would be 1638 calories per day.
If a completely sedentary person consistently eats 500 calories more than she needs to maintain her current body weight, she will gain weight until her new resting metabolic rate matches how many calories she eats each day. For example a 40 year-old 5 foot 4 inch woman weighing 140 pounds who does nothing but lie around in bed all day needs 1377 calories every day to maintain her weight. If she instead eats 1877 calories every day, she will gain weight until her new resting metabolic rate equals 1877 calories, which happens when she weighs 255 pounds.
Unless you never get out of bed, the amount of calories you use in a day is considerably more than your resting metabolic rate. Any time we move any muscle we use up more energy than our resting metabolic rate. If you are sitting at a desk doing office work such as writing or typing, you are using calories about 1 1/2 times as quickly as your resting metabolic rate. When you are standing and moving around doing light housework your body is burning calories about 2 1/2 times your RMR. Walking slowly causes you to use about 2 1/2 times your RMR, but walking quickly for exercise uses about 3 1/2 times your RMR. If instead of walking you decide to jog, cross country ski, or backpack, you will use energy at a rate of about 7 to 9 times your RMR.
For example, a 40 year-old 5 foot 4 inch woman weighing 200 pounds has a resting metabolic rate of 1638 calories per day, or 68 calories every hour. So when she is sleeping or reclining watching television, that is how many calories her body requires. If she has a desk job, she will burn calories at a rate of 1.5 times her RMR while at work, or about 102 calories per hour. While she is walking around the house and doing light housework, she will burn calories at a rate of about 2.5 times her RMR, or about 170 calories per hour. If she decides she needs more exercise and goes out jogging, she will use calories at a rate of about 544 calories per hour. This means that if she spends an hour jogging instead of sitting at her desk, she will use 442 calories more than she would have if she had not gone jogging. For every hour she spends walking instead of sitting, she is burning an extra 68 calories.