Make the most of your metabolism

"It's my metabolism!"

Sound familiar? If you're carrying some extra pounds (and having a hard time losing them), it's tempting to put the blame on a sluggish metabolism.

However, is your metabolism really the reason it's often so hard to lose weight? More importantly, is there anything you can do about it?

We asked experts to explore the facts and myths about metabolism - and the good news is, there are things you can do to help boost your body's calorie-burning power.

What is metabolism?

Your metabolism, experts say, involves a complex network of hormones and enzymes that not only convert food into fuel but also affect how efficiently you burn that fuel.

"The process of metabolism establishes the rate at which we burn our calories and, ultimately, how quickly we gain weight or how easily we lose it," says Dr Robert Yanagisawa, director of a weight management programme at Mount Sinai Medical Center in New York.

Of course, not everyone burns calories at the same rate.

Your metabolism is influenced by your age (metabolism naturally slows down by about 5% per decade after 40 years old), your sex (men generally burn more calories at rest than women) and your proportion of lean body mass (the more muscle you have, the higher your metabolic rate tends to be).

Heredity also makes a difference.

"Some people just burn calories at a slower rate than others," says Barrie Wolfe-Radbill, a nutritionist who specialises in weight loss.

Occasionally, Yanagisawa says, a defect in the thyroid gland can slow metabolism, though this problem is relatively uncommon.

Here's a fact that may surprise you: the more weight you carry, the faster your metabolism is likely to be running.

"The simple fact is that the extra weight causes your body to work harder just to sustain itself at rest, so in most instances the metabolism is always running a bit faster," says Molly Kimball, a sports and lifestyle nutritionist.

That's one reason it's almost always easiest to lose weight at the start of a diet, and harder later on. Kimball says, "When you are very overweight your metabolism is already running so high that any small cut in calories will result in an immediate loss."

Then, when you lose significant amounts of body fat and muscle, your body needs fewer calories to sustain itself, she says. This helps explain why it's so easy to regain weight after you've worked to lose it.

If two people both weigh 14 stone, with one of them always at that weight but the other one slimming down from 20 stone, Yanagisawa explains, “the one who got there by cutting calories is going to have a slower metabolism." In other words, the person who had to lose weight will require fewer calories to maintain their weight at 14 stone than the person who never went beyond 14 stone.