Even when you are sitting at rest your body is not resting. Your heart is beating, you are breathing and your body is carrying out other functions that you are unaware of entirely. Your body may be making blood cells, your kidneys may be eliminating wastes and your liver may be clearing toxic substances from your body. Your brain is burning calories as it acts as the master control center coordinating all of these activities. This is work that your body must do to keep you functioning. This work involves making new cells or tissues, breaking down old cells or tissues, or repairing and maintaining existing cells and tissues. All of this work is collectively referred to as your metabolism. It should not be surprising that this work requires energy. You are burning calories even when you sit quietly at rest.
What is “Resting Metabolic Rate”?
The rate at which your body burns calories when you are comfortably resting is called your “resting metabolic rate” or RMR
There is only one way to know for certain if you have a slow metabolism and that is to measure it. Regardless of which system is used, the rate at which your body uses oxygen while at rest is measured. Without going into the technical details, measuring your rate of oxygen consumption allows calculation of your RMR. Your RMR is the number of calories you burn over time. If we know your RMR, we can easily calculate the number of calories you burn over an entire day if you were to remain at rest.
Why You Need To Know Your RMR
When you cut calories to BELOW your RMR, your body fights back. Restricting calories below your RMR is like asking your car’s engine to run on too little gas. If your car is sitting in the driveway with the engine on, it is burning gas as it sits there. If you put the car in drive and step on the gas, it burns gas at a faster rate. What happens if you choke off the supply of gas to your engine? It sputters and eventually stalls. The same is true for your metabolism.
- Introduction: Why You Need To Know Your RMR
- Part 1: What Is “Metabolism?”
- Part 2: What happens if you cut your food intake BELOW your RMR?
- Part 3: Food Is More Than Calories