Web MD explains that metabolism 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 Robert Yanagisawa, MD, director of the Medically Supervised Weight Management Program 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 about 5% per decade after age 40); your sex (men generally burn more calories at rest than women); and proportion of lean body mass (the more muscle you have, the higher your metabolic rate tends to be).”

I’m a big fan of metabolism and have read lots of articles about it, but I’m still not sure I understand all the intricacies.

I understand that to boost your metabolism, you should eat plenty of protein and iron-rich foods. You can rev your metabolism by eating smaller meals more frequently. German researchers even found something as simple as drinking ice water can raise your resting metabolism by about 50 calories per day. (That doesn’t seem like much, but it can help you lose five pounds in a year.)

Bodybuilder Chris Aceto wrote a good analogy. “If you’re earning $4000 a month, but your boss suddenly cuts your pay to $2500 a month, you will try to live the same lifestyle on $2500 a month as you did on $4000 a month. After a while, you have to adjust and save money, and change your lifestyle. The same is true with a calorie intake that is simply too low. When calories are cut below basal metabolic needs, the body will accommodate and slow its metabolism, so it becomes difficult to lose fat even on low calories.”

Okay, I get all that.

But how low is too low when it comes to calories? How do you know how many calories you should be eating and burning to keep your metabolism humming along like a finely tuned machine?

I’ve told you before I’m a big fan of the delightful Charlotte over at The Great Fitness Experiment. Recently she wrote Slow Metabolism — Fact or Myth.

The entire article was interesting and entertaining, as always, but this caught my attention:

“During this time, I had my metabolism thoroughly tested – both in the doctor’s office (they ran tests on my thyroid and my hormones and even my baby maker – which thankfully was unoccupied at that time) and in the gym via hydrostatic weighing and the Darth Vader-on-a-treadmill metabolic testing. Their conclusion? I need 1242 calories a day to go about my daily life.”

I remember asking someone — my doctor? Nutritionist? Hairdresser? — if there was a way I could test my metabolism. While I don’t remember which type of professional I discussed this with, I specifically remember their answer. “No.”

But now Charlotte tells me differently. Yay! A new quest! I will keep you posted, but in the meantime, tell me any of your experiences with metabolic testing.

Have any of you (besides Charlotte) had your metabolism tested in this way? What did it involve? Did it cost a gazillion dollars? How many calories do you need every day?