Get your motor revving

Dieting is really about math.

You count the calories you eat. You count the calories you burn. If the equation tilts in one direction, you lose weight. If it leans the other way, you gain.

But figuring both sides of that equation is not so simple.

It's easy -- though, admittedly, tedious -- to add up the calories in the skinless chicken breast and plain salad you packed for lunch.

It's much harder to compute the calories you burn walking across the parking lot or taking the stairs to your third-floor office.

That number will vary depending on your size, age, gender and general health. Heavier people will use up more calories. If your body contains more fat than muscle, you'll burn less. As you age, your metabolism naturally slows.

With so many variables, formulas used to estimate a person's metabolic rate aren't always accurate.

"The human body is hugely individualistic," said personal trainer Gregory Florez, founder of FitAdvisor.com and a spokesman for the American Council on Exercise. "Our motors rev at a different pace."

Learning how fast your metabolism runs can be a key piece of information for dieters, just like knowing your target heart rate and body fat percentage, Florez said.

Getting this information used to mean shelling out hundreds of dollars at a high-tech performance lab. Today, with cheaper, portable equipment, most fitness centers can test your metabolic rate for under $100.

These devices calculate your resting metabolic rate by measuring how much oxygen you consume while you breathe into a tube for 10 to 15 minutes. The resting metabolic rate represents how many calories your body needs simply to survive -- to breathe air, pump blood and perform other vital functions.

"For people who are sedentary, their resting metabolic rate can make up 70 percent of their total calorie burn for the day, which is a huge number," said Dana Petersen, a dietitian at Condell Health Network in Libertyville.

"If we can figure that number for sure, we have a huge chunk of the equation to more accurately determine how many calories a person needs," she said.

A metabolism test can help you design a new diet or get past a plateau. Here's how three dieters we've been following this year used metabolic testing to fine tune their efforts to lose weight.

Reality check

Barbara Goetzelman of Antioch had struggled for seven months to lose weight, but had only lost a few pounds, which she regained. She had tried eating more vegetables. She'd learned about sensible snacks. She added walking and regular strength workouts to her routine, but nothing worked.

So dietitian Dana Petersen at Condell Medical Center in Libertyville suggested metabolic testing.

The result: It's not a lagging metabolism that's to blame for Goetzelman's stubborn pounds. She's just eating too much.

The test showed her resting metabolic rate is 1,640 calories per day, just a little faster than the 1,616 that is typical for a woman her size and age.

That means her body needs about 1,640 calories just to support basic functions like breathing. Going about her daily life will burn more calories, and so will exercise. To maintain her current weight, Petersen estimated Goetzelman needs about 2,200 calories a day. To lose a pound a week, Petersen recommended about 1,700.

Petersen also gave Goetzelman a custom meal plan specifying what types of food to eat at breakfast, lunch, dinner and snacks. The new plan also clearly defined portion sizes; a serving of pasta is a meager one-third cup.

You can eat several servings of pasta at a single meal, Petersen told Goetzelman, but you'll have to watch your total daily intake of starches.

The information was eye-opening for Goetzelman.

"I think I was eating too much," she said. "When I looked at the serving sizes for meat, I was way over. And for cheese. I grew up with cheese and I dearly love it. I think I didn't have any idea how many calories I was taking in every day."

So far, the new plan seems to be working. She lost 3 pounds in the first week and a half, bringing her weight down to 226.

"Whatever is going on, it seems to be making a difference," Goetzelman said.

Revving up

When Michael Raczak of Naperville started working out five or six days a week, he changed the makeup of his body.He lost 22 pounds and built muscle. His body is now 24 percent fat, an improvement over the 31 percent fat he measured in February.Muscle burns more calories than fat, so a person with a higher muscle mass will have a faster metabolism. This is Raczak's first metabolism test, so he can't compare it to his pre-diet result. But the test does show his metabolism is faster than average.Raczak's resting metabolic rate is 2,203. If he adds 660 calories for his daily activities and 500 for his hefty workouts, his total metabolic rate is over 3,300.Compared to other men his age and size, Raczak's metabolism is 29 percent faster, said Robert Hubbard, fitness supervisor at Edward Health Fitness Center/ Seven Bridges in Woodridge, who administered the metabolic test."That's very good," Hubbard said. "Fast is good, especially if you're looking to lose weight."It also sheds new perspective on advice from dietitian Nancy Rodriguez of Edward Hospital in Naperville. She told Raczak he should eat more."Just like a car, you can't go as far if you don't put gas in it," she said. "You could increase your calorie intake and still see results because you're running so much."Raczak has followed her advice, at least some of it. Before his long runs, he does try to eat a bit more. And now he's added a post-workout snack."I actually feel better if I can eat an hour or two after I'm done," he said. "I didn't always do that."But he's reluctant to increase his calories much over 2,000 a day. He still hopes to shed a few more pounds to reach his goal weight of 175.On Sept. 9, Raczak ran in the Chicago half marathon, finishing in just over two hours, six minutes. That's just a few minutes slower than his best time in the race in 2003.Holding steadyLynne Pieroni of Hanover Park has used her metabolic rate to gauge progress on her diet. When she began in January, she weighed 200 pounds and had a resting metabolic rate of 1,770.Based on that, dietitian Susan Rizzo of Alexian Brothers Hospital Network in Elk Grove Village advised a 1,400-calorie diet. When that wasn't enough to fuel Pieroni's intense workouts, they added snacks before and after each exercise session.Pieroni continued to lose just under a pound a week on a 1,600-calorie diet.In August, Rizzo tested her resting metabolism again. Exercise can rev up your metabolism, and so can increased muscle mass. Pieroni had both, leading Rizzo to expect her metabolism would increase.It hadn't budged. Pieroni scored 1,750.What happened? Over those seven months, Pieroni lost nearly 30 pounds. When you weigh less, your body needs fewer calories.Pieroni's weight loss probably offset her higher muscle mass and activity, Rizzo said.The new result helped Rizzo decide Pieroni should continue on her current diet. At 167 pounds, she's nearing her original goal to weigh about 160 -- what she weighed when she had her first child.She's also seeing progress in other measures. Her body mass index is 31, down from 36, and her body fat percentage is 35 percent, down from 43 percent in January. Her pulse is 64, down from 78. Her glucose levels have dropped, too, down to 100, instead of the pre-diabetic 115 she scored in January.The one stubborn number remains Pieroni's cholesterol. Despite a focus on cutting saturated fat and increasing soluble fiber, Pieroni's cholesterol recently measured 242, which is 10 points higher than it was in April.Part of the increase is good; her HDL, or "good" cholesterol, went up to 44, from 41, thanks to all her exercise. Her LDL of 167 is probably due to genes, and may only respond to medication, according to Dr. Janet Collins, medical director of the Partners in Prevention program at Alexian Brothers Hospital Network in Schaumburg.But in other ways, Pieroni is climbing high. Bill Jensen, Pieroni's personal trainer at Continental Athletic Club in Rolling Meadows, now gets her to run up 13 flights of stairs at the start of each workout."When we started to do the stairs, we did four flights and she was knocked out," Jensen said. "I can't tell you how proud I am of this lady."Barbara GoetzelmanAge: 59Height: 5 feet 5 inchesWeight: 226Daily calories burned at rest: 1,640What she learned: Her metabolism is normal; she needs to cut more calories to lose weight. Michael RaczakAge: 55Height: 5 feet 11 inchesWeight: 178Daily calories burned at rest: 2,203What he learned: A fast metabolism means he can eat more without gaining.Lynne PieroniAge: 48Height: 5 feet 2 inchesWeight: 167Daily calories burned at rest: 1,750What she learned: Increased muscle mass has kept her metabolism steady despite a 30-pound weight loss.Szopa meets goal to lose 30 poundsFred Coombs: 'I quit trying to quit' smoking 437512Michael Raczak has his metabolism tested in Naperville.Ed Lee | Staff Photographer 512413Ron Szopa of Elgin holds newborn Isabella in July.George LeClaire | Staff Photographer 512312Barbara Goetzelman of Antioch prepares food for a family party.Paul Valade | Staff Photographer 512357Lynne Pieroni runs up the stairs with trainer Bill Jensen at Continental Athletic Club in Rolling Meadows.Bill Zars | Staff Photographer