TO YOUR HEALTH: How To Boost Your Metabolism

Unless We Perform Regular Strength Exercises, We Lose 5-7 Pounds of Muscle Every Decade After the Age of 25. That Corresponds With a Reduction of up to 20% in Metabolic Rate Each Decade. The Result: You Get Weaker and Fatter. 

Metabolism is the process by which your body makes and uses energy, or calories, for everything from the cellular absorption of nutrients to running a marathon.

Each of us has what is called a basal metabolic rate (BMR), or one's base metabolism. A good technical definition of BMR is "the energy expended when an individual is lying at complete rest, in the morning, after sleep, in the post-digestive state."

For most men, BMR accounts for 60 to 70 percent of total calories expended each day, and that's a good thing, as you're about to see. Your BMR consumes all those calories through such functions as breathing, digestion, blood circulation, immune response and tissue repair. For comparison's sake, activity of any sort generally makes up just 15 to 30 percent of the average man's metabolism.

Muscle is the single most important predictor of how well you metabolize your food, and how well you burn calories and body fat. Regular exercise boosts your metabolic rate by producing larger mitochondria in each muscle cell, which results in more calories burned. Whereas fat is inactive and burns very few calories, skeletal muscle burns at least 10 times more calories than fat, even when we're at rest.

But unfortunately, unless we perform regular strength exercises, we lose more than a half a pound of muscle every year after the age of 25. Without an appropriate training stimulus, our muscles gradually atrophy, and decrease in size and strength. This loss of muscle results in a significant reduction in metabolic rate in every decade of adulthood -- as much as two percent a year. And the corresponding decrease in metabolism generally results in an increased ratio of fat mass, which usually escalates as we get older.

The average male and female between the ages of 20 and 50 loses 5 to 7 pounds of muscle per decade and adds three times as much fat during that period. Since metabolism usually slows with age, your eating habits need to change accordingly or else fat can accumulate and your weight can increase.

So, if you're in your 30s or 40s, have been eating exactly the same way for 20 years, and can't understand why you're gaining weight, it's because your energy demands have dropped.

The key to staving off the decline in your BMR is weight training. Strength training, at least twice a week, is essential to boosting your metabolism. The effects of a good, consistent strength training program allow you to continue burning calories 24 hours a day -- long after you've left the gym.

Tissue repair and maintenance are critical to caloric expenditure since about three-quarters of variability in BMR is predicted by lean body mass. Simply put, the more muscle mass you have the higher your BMR will be.

Untrained men and women can gain about 2 to 4 pounds of muscle, and 40 to 60 percent more strength, after just two months of regular strength training exercise.

But what you eat can also have a dramatic affect on your body composition. Some of the calories you consume are less likely store on your waistline. It's all about the choices you make.

Plenty of metabolic energy is required to convert the food we eat into usable forms of energy. The process of digesting, using, and storing food energy is inefficient, and by itself can consume from 10 to 15 percent of total daily metabolism. Animal proteins increase thermogenesis more than vegetable proteins, so the best calorie-burning foods are lean meats.

During the digestive process, foods are broken down into usable forms; complex carbohydrates are reduced to simple sugars, fats to fatty acids, and proteins to amino acids.

Eating protein with each meal is important. Protein contains nitrogen, which is broken down and eliminated as urea by the liver. As a result of this additional metabolic step, protein's thermic effect is roughly double that of fat and carbohydrates.

Assuming that you are exercising regularly, eating every 2 to 3 hours and including at least some protein with each of those meals can boost digestive metabolism all day long. And after you reach a healthy, stable weight you need to make sure you're eating as many calories as you're burning in order to maintain that weight.

If you have a job in which you sit all day, the following may be disheartening but also quite revealing; the difference in calorie burn between sitting and standing is nearly 1 calorie in added expenditure per minute. That may not seem like much, but it adds up quickly. At the end of an hour it amounts to 60 calories and at the end of an eight-hour workday nearly 500. Burning 500 extra calories a day for a week would result in the loss of one pound. That's over fifty pounds in one year. You get the picture.

The idea is to get up and get active. Committing yourself to a regular strength training program at least 2 to 3 times per week will make a big difference, and not just to your metabolism. The positive affects are numerous, including: increased bone mass and strength, decreased blood pressure, injury prevention, improved appearance and body composition, improved mood, confidence and self-esteem, as well as reduced stress.

And if you're doing all that work to strengthen and improve your body and your psyche, make good food choices that will leave you guilt free. Include plenty of protein at each meal to allow your body to rebuild what's being broken down in the gym and remain more metabolically active all day long. Remember to include lots of fruits and veggies because they're full of water and nutrients, and are low in calories.

Take care of yourself. You only have one body, and replacement parts are hard to come by.

"The doctor of the future will give no medicine, but will interest his patients in the care of the human frame, in diet, and in the cause and prevention of disease."
- Thomas Edison

"Let thy food be thy medicine, and thy medicine be thy food."
- Hippocrates, the Father of Modern Medicine

Sean is a freelance writer in Los Angeles. He has been working in the health and fitness business for a decade; training, teaching, lecturing, and consulting. 

To Your Health provides information on health, fitness, diet and nutrition. It is intended to help you improve your wellness and everyday living, specifically through the means of regular exercise and healthy eating.

Copyright © 2007 Sean M. Kennedy. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed without the author's consent.