The formula everyone always hears about weight loss is “calories in, calories out” — burn more calories than the number you consume, and you’ll slim down. That’s why you’ll see folks carefully scrutinizing the digital displays of their elliptical machines to determine exactly how much they’ve accomplished over the past hour.

But for a better figure, you should be thinking about another figure: How many calories are you burning after you hit the showers?

Tanya Colucci, the wellness director at Mint Fitness in Washington, has a way to keep torching through calories even the next day. “Get your muscular system to do as much as possible in a short period of time,” says Colucci, who also is president of the Infinity Wellness Foundation, which is dedicated to fighting childhood obesity.

The method, called Metabolic Density Training (MDT), takes two forms. You can pick a couple of exercises — say, deadlifts and stability ball push-ups — and perform each for a minute, constantly switching back and forth with minimal rest for as long as you can manage. Or, you can string together a series of total-body exercises that require explosive power in addition to strength. (For example, a single-arm dumbbell split snatch: Start in a squat holding the weight down in one hand, then jump into a lunge while lifting the weight above your head.) With those, you go for a certain number of reps rather than time, and once you get through the grueling routine, you do it again and again.

This structure may sound similar to circuit training, but the difference with MDT is the intensity. Instead of using moderate weights and getting an aerobic effect, you’re relying on heavy weights to achieve an anaerobic one. That means you can’t keep it up for nearly as long — 20 to 30 minutes at most — and you’re burning more calories both during the workout and beyond.

Every bout of strenuous physical activity creates some sort of afterburn effect. The technical term is excess post-exercise oxygen consumption, or EPOC. “The more intense the exercise is, the longer it takes the body to come down to a resting state,” she explains.

Nothing is more intense than MDT, which is why it’s certainly not for everyone. Colucci introduces only her most advanced clients to the technique. “If you hate sprinting all-out, it’s that feeling the majority of the workout,” she says.

Given what you can accomplish in such a short period of time, though, Colucci’s found that it’s ideal for people with busy schedules looking to “kick it up a notch” — including her. You can take a look at a sample workout on her Web site (tanyacolucci.wordpress.com/2009/11/12) or find similar routines at Crossfit.com.

However you do it, just be sure to end with a cooldown. It’s the calories you want to keep burning for days, not your muscles.