So it’s, what,  day 13 of the New Year — And I haven’t lost a pound despite the fact I’ve been starving myself!!!

That, says Kara Mitchell, a dietician and director of the Fitness Program at the Duke Health and Fitness Center in Durham, may well be your problem. “The biggest mis-conception for weight loss is that the more you deprive yourself, the more weight you lose. But that does not help you lose body weight.”

You’ve probably heard that before. And it probably got buried under a load of babble from weight-loss programs with their own slant on what you really need to do to lose weight. While some of those programs may work, Mitchell says through it all, amid all the commercial chatter, you need to remember three words: Resting Metabolic Rate.

Each of us have our own, unique Resting Metabolic Rate, which reflects the amount of calories our bodies need to perform basic functions: breathing, circulating blood, adjusting hormone levels, and growing and repairing cells, according to MayoClinic.com. Your RMR is based primarily on your weight, height, gender and age. Here’s why those factors are important, according to MayoClinic.com:

• Height and weight: The bigger you are the more calories you burn, even at rest.
• Sex: Sorry, gals, but men generally have less body fat and more muscle, and since muscle tissue burns more calories than fat, guys burn more calories, even if they’re just sitting in front of the TV watching football.
• Age: Apologies here to my fellow AARPers, buy as you age you typically have less calorie-burning muscle tissue and more fat.

Say you’re me, a 5’9”, 170-pound, 53-year-old guy. Your base calorie consumption, your Resting Metabolic Rate, would be 1600 calories per day. Mitchell says that if I were to go below my RMR, my body would start sending up red flags. Ahh-OOO-gah! Ahh-OOO-gah! My primal survival instinct would kick in and my body would start requiring fewer calories to maintain those basic functions of breathing, circulating blood, growing and repairing cells. My body doesn’t know I’m trying to lose weight; deep down it still remembers waaaay back to those days on the savanna when me and my cavepeeps may have gone a week between kills without eating.

I figured out my RMR using one of the many online calculators that will compute your RMR and its close cousin, the Basal Metabolic Rate. (For an explanation of the difference between the two, go here.) Mitchell says that will give you a good ballpark of your RMR, but for a more accurate reading you need should have your breathing measured as well. At Duke, that process involves sitting in a La-Z-Boy with a bubble over your head for a half hour to 45 minutes. That’s followed by an analysis of the results and a counseling session on how to get the most out of your base calorie needs. If you’re also embarking on a physical fitness program, the session can look at what you’ll need, calorie-wise, to keep from going below your RMP.

Mitchell says such nutritional counseling sessions can be arranged through your doctor’s office. At Duke, the cost of the analysis and nutritional counseling session is $100. Mitchell says the sessions aren’t covered by most health insurance programs (Duke Select, available only to Duke employees, and Blue Cross Blue Shield of North Carolina being the exceptions). But, she adds, the number you walk away with, your RMR, could mean the difference between finally starting to lose weight and winding up in this same place 13 days into 2011.

“Your metabolism responds to change,” Mitchell says. “Make sure you know what your number is and don’t go below it.”

Tomorrow: Kara Mitchell returns with some tips on how to eat and get the most of basic calorie count.
Photo: Sitting in a La-Z-Boy for 45 minutes could be your first step to finally losing weight.