Metabolism Part I

Metabolism is a medical term often thrown around when it comes to weight loss, but what does it really mean and do you have any control over it?

In simple terms, metabolism is the chemical reactions (energy) needed to sustain life. This energy is usually calculated in terms of calories when it comes to food consumption. The rate your body burns these calories to sustain life and do daily activities is known as metabolic rate. If you match the calories you take in with your metabolic rate you will maintain your same weight. More calories then your metabolic rate, you will increase in weight; and like wise, with less calories then your metabolic rate you will decrease weight. While this equation seems rather simple (and it is) the process your body and brain uses is a little more complex.

This whole process is controlled by hormones from your thyroid gland which gets its signals from the hypothalamus, a portion of your brain. This process is similar to your heart rate, in that it is not under your conscious control. You can’t really think your heart rate faster or slower to whatever rate you want it to be. But you can indirectly change your heart rate by what you do. Start running up some stairs and your heart rate will go up. Stop and lie down for awhile and it will go down. So you can’t really think your metabolic rate to speed up or slow down, but there are things you can do that will change your metabolic rate. Your brain is taking in all sorts of info from the body and calculating what it thinks your metabolic rate needs to be to allow you to survive for the next few days.

Your metabolic rate is primarily made up of three things: Basal Metabolic Rate (BMR), activity and thermogenesis. Your BMR is the energy your body needs to sustain life with no real activity except to be at rest. So even when you are sleeping your body still needs energy to keep all your cells and systems alive and working, your heart pumping, muscles to allow for breathing and your brain to keep working. In general your BMR is about 60% of your total metabolic rate. Next is your activity level which is about 30% of your metabolic rate. Obviously we all know the more active you do the more calories you burn. The last is thermogenesis, which is about 10% of your metabolic rate. This is the thermal effects of the food you eat; it requires energy to get the energy from food into a form that our body can use.

Just a few other side notes about metabolic rate before we get into what you can do to change your metabolic rate for your benefit when it comes to weight control next week. There are medical conditions that can slow your metabolism for example hypothyroidism and Cushing’s syndrome. While these are very rare, they do happen, so if you have extreme fatigue, depression, dry skin, hair loss along with decreased sex drive you may want to see a physician to do a few simple tests to see if you have these medical conditions. If you don’t have either of these medical conditions then you can use the info on how to boost your metabolism we will get into next week.