Metabolism is the term used to describe the chemical process inside living cells that is necessary for the maintenance of life. This means ALL living cells: skin, blood, brain, and internal organs. Metabolism is not a process isolated to one specific organ as many think, rather it's a process dealing primarily with the stomach and intestinal organs. Reading this right now? Metabolism plays a part in doing that. Eating breakfast? Metabolism. Sleeping, shivering, muscle contractions, thinking, literally all chemical processes necessary for life are part of metabolism. Every cell in the body contains structures called mitochondria, the "power-house" of the cell. Mitochondria turn the calories you eat into energy. They not only produce energy but they break down compounds such as proteins, carbohydrates, and fat, and they produce the energy necessary for your body processes.
Why does my metabolism slow down?
As you age, free radicals form (these are unstable molecules that are missing an electron), and these are not good to accumulate. They try to regain stability by "taking" the nearby stable molecules electrons in your body, thus making that molecule unstable. This destruction begins to stack up. After a while, that "taking" of extra molecules will begin to affect your DNA and your response to calorie intake begins to dissipate.
How do I keep my metabolism from slowing down?
The key is to eat well, exercise regularly, and get a good night's sleep for recovery. Think of your muscles; if you don't use them, you lose them. Metabolism is the same way; if you don't take care of it, it fades away. Your metabolism will not slow down with age if you give it the attention and fuel it needs to stay running "young."
Is there a way to "boost" my metabolism?
The best way to boost your metabolism is to take care of your body and exercise to keep the mitochondria within your cells working efficiently. Again, it's more than what you eat; it's about your lifestyle. Eat a well balanced diet (avoiding foods that increase free radicals in the blood), exercise regularly, and sleep 7-9 hours a night, that restful sleep gives your cells time to "rejuvenate" and continue to run smoothly.