SEATTLE TIMES/JIMI LOTT VIA KRT Kiwan Williams, right, works out at Whidbey Island Naval Air Station. The Navy is trying to make sailors more fit.

SEATTLE TIMES/JIMI LOTT VIA KRT Petty Officer Jimmy Miller is working to shed the 80 or so pounds he needs to lose in order to meet Navy weight requirements and stay in the service.

SEATTLE TIMES/JIMI LOTT VIA KRT Dede Neal, front, sprints from the starting line during an aerobics class. Jimmy Miller, who has been commanded to lose weight to stay in the Navy, is at far left.

Twice a week, Petty Officer Jimmy Miller breaks from his duty of surveilling the Pacific Ocean for enemy submarines to attend an aerobics class. The naval sonar technician isn't shirking his wartime responsibilities; he's just following orders.

At 250 pounds, the 5-foot-10-inch sailor has been commanded to shape up or ship out.

Barely under the weight limit when he joined the Navy nine years ago, Miller, 29, steadily packed on pounds, especially during the five years he spent on a ship, and has failed a series of weigh-ins.

Now mandated to participate in High-Energy Athletic Training (HEAT) -- an aerobics class tailored to trimming down sailors stationed at Whidbey Island Naval Air Station -- Miller has shed 15 pounds. But he remains about 80 pounds over Navy weight standards and risks being rejected when he comes up for re-enlistment in the fall.

"I'm trying not to focus on that because it's really a minor concern compared to [Iraq]," Miller said.

But the military's concern -- like its waistlines -- is growing. Like Miller, many U.S. troops have put on the pounds. Nearly 1 in 5 active-duty personnel are overweight, according to a Department of Defense survey.

Loath to dismiss service members in whom they have invested time and money training on the sole charge of a potbelly, the military is stepping up efforts to slim down its men and women in uniform.

The Defense Department in November issued weight and body-fat standards for the first time, and it has ordered all branches to begin submitting data on overweight personnel in their ranks by next year. The Army commissioned the Institute of Medicine, a branch of the National Academy of Sciences that advises the government on medical issues, to issue weight-management recommendations; the resulting report is expected to be released this spring.

On bases, aircraft carriers, even submarines, the services are developing fitness programs.

The focus is relatively new for the military. Until 1960 there were no upper weight standards in the services; weigh-ins were intended to detect soldiers who were too scrawny.

"There is no question soldiers are getting bigger -- just look at photos of soldiers from the '50s," said Lt. Col. Karl Friedl, the Army's director of operational medical research, adding that this trend simply reflects the across-the-board weight gain seen among the general population. But he emphasizes that the military's growing girth doesn't impair U.S. readiness.

"You can carry a little bit more fat and still be fit," Friedl said. "War is not a marathon; it doesn't require skinny, it requires strength."

A certain level of size can provide advantages on the battlefield -- being able to hoist a 100-pound pack, for instance. However, excessive weight can make troops more susceptible to heatstroke, injuries and health conditions such as diabetes, arthritis and heart disease, which impair performance and drive up the military's medical expenses, Friedl said.

The military's weight problem is far from the epidemic seen among the U.S. civilian population, where 60 percent of people over 20 are overweight. But the problem is growing: The Defense Department's most recent statistics show 19 percent of service members were overweight in 1998, up from 16 percent in 1994. Among most age groups, the Navy was the heaviest branch and the Marine Corps was the trimmest.

And unless the brass's efforts make a difference quickly, the state of the general population suggests that trend will likely continue. Many 18-year-old Americans who show up at their local recruiter's office are too pudgy to get into the service, Friedl said. A study published last fall showed that 13 percent of men and 17 percent of women of prime recruitment age -- 17 to 20 -- would fail weight requirements for all four services.

Fitness requirements vary across the military branches, but essentially, every six months service members are required to take a fitness test, which, in the Navy for instance, involves a timed run or swim, sit-ups, push-ups and a toe-touch stretch. They also have a weight check, and if they tip the scales, they are subjected to the more accurate body-fat test.

When military personnel fail either the fitness test or body-fat check, they are placed on a remedial program in which their exercise routine is monitored.

Miller, who passed his fitness test but was over his allowed body fat by 6 percentage points, is required to attend HEAT classes twice a week and run once a week.

Some branches may discharge personnel if they fail to show progress -- between 2,000 and 4,500 people each year are dismissed from the military for being overweight -- but three years ago the Navy stopped the practice.

"We were separating too many people for physical-fitness failures; there was anecdotal evidence that people were eating their way out of the Navy," says Tim Cepak, Navy Physical Readiness Program manager.

Now the Navy bars overweight sailors from advancement and weeds them out by refusing to re-enlist them when their service contract expires every four years.

The problem isn't as dire as the statistics suggest, said Dr. Richard Atkinson, director of the American Obesity Association and a member of the Institute of Medicine panel studying weight control in the military. The statistics of overweight soldiers are based on body mass index (BMI), a ratio of height to weight, which he says casts a distorted picture.

He points out that many military personnel are heavily muscled, which would make them weigh more than a typical civilian, so while their weight places them in the category of "overweight," they may actually be quite fit.

In a survey of nearly 1,400 Army soldiers at three posts in December, Friedl found that 11 percent of men and 17 percent of women soldiers were over fat standards. This finding, rather than the 19 percent figure based on BMI, represents the true magnitude of the problem, he said. That's why BMI is used only as one part of the military's weight-screening process.

To give more leeway to beefy soldiers, the military's BMI standards are looser than those used in the civilian population, which deem overweight a BMI over 25.

In the services, those with a BMI over the limit -- the standard varies by branch but ranges from 25 to 27.5 -- are subjected to a body-fat test. A tape measure is used to check the circumference of the neck and waist, plus hips for women. These measurements can be used to calculate whether someone has excessive body fat, which helps separate the fit yet overweight folks from the truly over-fat.

The maximum body fat allowed for men in the military is 18 to 26 percent; for women it's 26 to 36 percent.

In an attempt to shed the Navy's label as the chubbiest branch of the military, Navy Northwest is planning to open a first-of-its-kind facility called University of Fitness Beach near Ocean Shores this summer. Northwest sailors who want to remain in the Navy but have failed their fitness requirements can apply for a weeklong stay at the weight-loss camp.

At Whidbey Island Naval Air Station, the HEAT class was created a year ago to help sailors pass their weight and fitness tests. Several times a week, fitness instructor Melissa Crawford runs dozens of sailors through an hour of grueling drills.

The sailors barrel back and forth across the gym floor, drop for push-ups, turn over for crunches, then lower themselves into squats and spring into the air.

"We're dealing with a group of people who don't have a lot of skills for choreography, so I try to make it more like P.E. class," Crawford said.

Chief Petty Officer Tim McClain, who serves as command fitness leader for a team of 465 reconnaissance pilots and crew on Whidbey Island, said that during the last physical readiness test in November, 8 percent of his command -- 35 sailors -- failed, mostly the body-fat portion. So he ordered all of them to take the HEAT class three times a week.

He says he anticipates most will pass the test soon. But he says no matter how much he orders them to exercise, the hardest part is getting them to eat right. All military bases have fast-food restaurants. On Whidbey Island, the Big Mac is the downfall of many a good sailor, he said.

With his T-shirt drenched and cheeks ruddy after a recent HEAT class, Miller -- who admits a weakness for McDonald's -- said the class is pushing him to work out much harder than he would on his own, and he's hoping the increased intensity of exercise will help whip him into shape in time to save his naval career.

"I would like to stay in; my grandfather was in the Navy and my father was the Navy," he said. "But I'm starting to look over my options in case I can't lose enough weight and have to leave."