Saturday, September 13, 2008

Metabolism

What Is My Metabolism?

Your metabolism is the whole range of chemical reactions in your body's cells that turn the food you eat into living tissue, energy, and waste products. Your metabolism is a combination of two processes:

* catabolism, when food is broken down into simpler components. This is accompanied by the release of energy that heats the body, enables the body to move and provides fuel for anabolism;
* anabolism, when the body uses the energy released as a result of catabolism to make new cells, maintain body tissues and store energy for future use.

These two complementary metabolic processes are controlled by systems of hormones which switch your body from anabolic to catabolic mode and vice versa. One result of this metabolic switching system is that your body gains or loses weight.

Your daily calorie burn is affected by how much you exercise, the amount of fat and muscle in your body and your basal metabolic rate (BMR). Your BMR is the speed at which your body burns up energy (calories) while at rest. This can determine your tendency to gain or lose weight.

What Factors Influence My BMR?

Many factors affect your BMR:

* Genetics: Some of us are born with a faster metabolism and some with a slower metabolism.
* Gender: Men have a greater muscle mass and a lower body fat percentage so they generally have a higher BMR.
* Age: Younger people have more actively dividing body cells. Cell division consumes a lot of energy and that is why their metabolism is very fast. Your BMR declines approximately by 2% every 10 years after you turn 20.
* Height: The taller a person is, the higher their BMR because their body surface area is larger and so heat loss is greater.
* Body composition: It requires more energy to sustain muscle mass than fat. The more muscle mass you have, the higher your BMR.
* Glands: Thyroxin (produced by the thyroid gland) is a key BMR-regulator, which regulates the metabolic activity of the body. The more thyroxin produced, the higher your BMR. Adrenaline also increases your BMR but to a lesser extent.
* Hormones: Some surveys have found that a woman's metabolism dips just before ovulation and again at menstruation. BMR then starts to rise when the body temperature climbs. Menopause causes the metabolism to slow down.
* Stress: Stress hormones can raise your BMR.
* Exercise: This not only burns calories, it also helps raise your BMR by building extra muscle.
* Diet: Excessive calorie restriction, or starvation, can dramatically reduce your BMR.
* Stimulants: Your metabolic rate rises temporarily after ingesting caffeine and nicotine. This also raises your heart rate.
* Temperature: A low external temperature causes an increase in BMR. This creates the extra heat needed to maintain the body's internal temperature.

Can I Control My Metabolism?

Good news – yes, you can! Here are five practical and safe ways to boost your metabolism.

1. Exercise. It takes more calories to maintain muscle than fat. This is why the most effective way to boost your metabolism is to increase your muscle mass through exercise. Your metabolic rate rises temporarily during a workout and for up to an hour afterwards, in addition to the longer term rise due to increased muscle bulk.
2. Eat enough. A common mistake is taking in too few calories. This, as a rule, has an adverse effect. When you deprive yourself of calories, your body thinks it is in starvation mode and your metabolism will slow down to conserve energy reserves.
3. Eat breakfast. If you skip breakfast, this is a message to your body that you are starving because you haven't had food for at least 12 hours. As a protective mechanism, your metabolism slows down and the body starts storing fat. By having breakfast, you are telling your body that there is no danger of famine. Your metabolism is boosted which helps to burn excess calories.
4. Eat smaller, more frequent meals. Eating one or two huge meals each day will slow your metabolism and tend to make you gain weight. The reason is that your body doesn't get enough energy to function properly through the hungry periods. When you do eat your large meal your body is then primed to store some of the energy as fat. It is better to snack frequently on fruits, vegetables and grains.
5. Drink water. The recommended amount is eight glasses per day. Your metabolism needs plenty of water to function properly. Carry a bottle of water with you and drink frequently throughout the day.