New Year’s has come and gone, which means resolutions have been made (and possibly already broken). For those who have decided to make 2012 the year to shed unwanted pounds, you need to learn much more about your metabolism.

Metabolism is the biochemical process through which our body converts food and drink into energy. Dr. Ibrahim Salahat, medical director of International Medical Center-Beijing, says, “This energy is measured in calories, and it’s only by creating an energy deficit by expending more calories than we consume can we begin to lose weight.”

The key word here is “expending.” Many people think that simply by consuming fewer calories, they can achieve long-term weight loss. This is wrong. Doing so, in fact, could actually lead to weight gain, Dr. Salahat warns.

The reason has a lot to do with Basic Metabolic Rate or BMR. This is the minimum number of calories per day a body needs in order to carry out so-called “hidden body functions,” such as breathing, blood circulation, hormone adjustment and cell growth. This amount is dependent on a number of factors including sex, height, weight, age and level of activity, and can be calculated using the following equations:

Men: 66 + (13.7 x weight in kg) + (5 x height in cm) - (6.8 x age in years)

Women: 65 + (9.6 x weight in kg) + (1.8 x height in cm) - (4.7 x age in years)

“It is estimated that 60 to 75 percent of a person’s total daily calories go towards these ‘hidden’ body functions,” says Dr. Salahat. “This is why limiting daily calorie intake through fasting and dieting is bad for the body. After a while, the body shifts into survival mode by slowing down these natural bodily processes, leading to fewer calories burned and more calories stored as fat. And because no one can diet forever, the inevitable result is that you gain all the weight back, plus some.”

Thus, rather than deprive yourself of your favorite indulgences and entire food groups, incorporate more healthy foods into your diet. “Focus on quality not quantity,” advises Dr. Salahat. “For example, you could eat 10 pounds of cucumbers and still consume fewer calories than you would with a bar of chocolate—though I don’t recommend it,” he laughs.

The other major factor in weight loss: physical activity. In addition to the obvious upside, exercise has the added benefit of increasing muscle tissue, which burns more calories than fat tissue, according to Dr. Salahat. In other words, if we looked at two twins who were exactly the same in every respect besides muscle mass, the twin with more muscle would burn more calories at rest than the other.

As a general goal, Dr. Salahat recommends incorporating at least 30 minutes of physical activity per day—be it by running, walking the dog or doing housework. “If you can’t set aside time for a longer workout, try 10-minute chunks of activity throughout the day,” he says. “Remember, the more active you are, the greater the benefits.”

Of course, most of this is common knowledge. Yet, many people still revert to fad diets that involve mixing cayenne pepper and lemon juice or eating grapefruit for breakfast, lunch and dinner to melt away the pounds. The results may be obvious in the short term, but they’re not long term solutions. “In the end, only exercise combined with healthier food choices can result in safe and permanent weight loss. It’s as simple as that,” says Dr. Salahat.