Metabolism:
Have you wondered what makes a person have a high or low metabolism? Or have you ever felt that losing weight is impossible for you because your metabolism is so slow? Or that whether you exercise or not, you don’t lose weight? Maybe the following can help.
Have you wondered what makes a person have a high or low metabolism? Or have you ever felt that losing weight is impossible for you because your metabolism is so slow? Or that whether you exercise or not, you don’t lose weight? Maybe the following can help.
Energy and Calories:
Metabolism is about energy. Energy has a measurement. Weight has a measurement in pounds or kilograms, speed can be measured in miles per hour. Metabolic energy is measured in calories.
One calorie is the energy that is needed to increase the temperature of 1 gram of water by 1 degree Celsius. When we refer to eating and burning calories, it is actually 1,000 of these small calories or one kilocalorie (kcal). We continue to call them Calorie but spell it with a capital C.
Metabolism is about energy. Energy has a measurement. Weight has a measurement in pounds or kilograms, speed can be measured in miles per hour. Metabolic energy is measured in calories.
One calorie is the energy that is needed to increase the temperature of 1 gram of water by 1 degree Celsius. When we refer to eating and burning calories, it is actually 1,000 of these small calories or one kilocalorie (kcal). We continue to call them Calorie but spell it with a capital C.
Total Energy Expenditure:
Our metabolic rate or Total Energy Expenditure (TEE) is made up of three elements:
Our metabolic rate or Total Energy Expenditure (TEE) is made up of three elements:
- Digestion of Food (Thermogenic Rate) 10%
- Physical Activity (Active Metabolic) Rate 20%
- Energy for basic body processes (Basal Metabolic Rate) 70%
The Harris-Benedict Equation:
The Harris-Benedict Equation is the way we have been calculating the Basal or Resting Metabolic Rate (BMR) since 1919. Researchers today say that this equation is not entirely accurate. Every person has so many variables to consider, such as ratio of fat to lean muscle mass, genetics, activity level, menopause and many other things. Although it isn’t perfect, it is a good tool in helping to understand how much energy we need to consume and burn.
The Harris-Benedict Equation is the way we have been calculating the Basal or Resting Metabolic Rate (BMR) since 1919. Researchers today say that this equation is not entirely accurate. Every person has so many variables to consider, such as ratio of fat to lean muscle mass, genetics, activity level, menopause and many other things. Although it isn’t perfect, it is a good tool in helping to understand how much energy we need to consume and burn.
Calculating Your BMR:
- 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 )
Active Metabolic Rate (AMR):
Now, you can determine your Active Metabolic Rate (AMR) which is your BMR or resting rate plus the amount of energy you require for the level of physical activity you exert on a typical day. You multiply BMR number you calculated above times the number below which represents your typical level of activity.
Now, you can determine your Active Metabolic Rate (AMR) which is your BMR or resting rate plus the amount of energy you require for the level of physical activity you exert on a typical day. You multiply BMR number you calculated above times the number below which represents your typical level of activity.
Calculating Your AMR:
- If you are sedentary (little or no exercise): Multiply BMR x 1.2
- If you are lightly active (light exercise/work 1-3 days per week): Multiply BMR x 1.375
- If you are moderately active (moderate exercise/work 3-5 days per week): Multiply BMR x 1.55
- If you are very active (hard exercise/work 6-7 days a week): Multiply BMR x 1.725
- If you are extra active (very hard exercise/work 6-7 days a week): Multiply BMR x 1.9
A Caloric Example:
A typical 50-year-old female adult weighing 160 pounds has BMR of approximately 1555 k/cal per day. If she has a low level of activity, her AMR is 1555 x 1.2 for a total of 1866 k/cal per day. Now imagine if she consumes 2500 calories per day in her diet. It can be seen that weight gain can happen easily. For every 3500 calories that are consumed, but not burned, a person will gain one pound. If 500 extra calories are eaten per day, a person's weight could increase by 1 pound per week. The Metabolic Syndrome will compound the problem of weight gain. See Insulin Resistance in the Metabolism of Food topic.
A typical 50-year-old female adult weighing 160 pounds has BMR of approximately 1555 k/cal per day. If she has a low level of activity, her AMR is 1555 x 1.2 for a total of 1866 k/cal per day. Now imagine if she consumes 2500 calories per day in her diet. It can be seen that weight gain can happen easily. For every 3500 calories that are consumed, but not burned, a person will gain one pound. If 500 extra calories are eaten per day, a person's weight could increase by 1 pound per week. The Metabolic Syndrome will compound the problem of weight gain. See Insulin Resistance in the Metabolism of Food topic.
For more information see:
Sources:- Dohm, G.L. & Fushiki, T. (2002). Exercise treatment for obesity. Chapter 19. Endotext.com [online]. Accessed December 27, 2006.
- KETV. Calculate your BMR. [online]. Accessed December 27, 2006.
- Weil, R. (2003). WebMD. How fast is your metabolism? [online]. Accessed December 23, 2006.
- Wikopedia. Basal metabolic rate. [online]. Accessed December 22, 2006.