Washington (CNN) -- Tony Horton is on a mission: to keep the military fit.
As a fitness trainer, Horton knows a thing or two about the demands of military service. He has worked directly with members of the military at bases in the United States and abroad using his fitness program "P90x" as a model.
His workout signature line: "Bring it."
"A lot of the military right now are suffering like the civilian population: They're overweight and not exercising regularly and eating too much fat, sugar and salt," Horton told CNN. "So the idea is to rewire folks so that they can be as fit as they can possibly be."
His fitness program is helping military men and women fighting abroad, he said. The program does not require a gym -- just a DVD player in which to play the series of workout discs.
"So if you're in Afghanistan and downrange and you want to get a workout in, you can do it right there on the ground," he said.
Horton took his "Fit to Fight" pitch to the National Press Club on Friday to urge the military to fight obesity within its ranks. Of particular concern is whether the Department of Defense will be able to replace current fighting forces when potential recruits are too badly out of shape to qualify for service.
"[My program] is as much about recruits as it is about active duty," Horton said. "So it starts with the civilian population. We've got kids that actually want to join up and can't because they can't pass the PT [physical training] test."
A recruit must meet the physical fitness test, which includes situps and pushups, when he or she enlists.
The maximum acceptable weight depends on the person's age, gender and height. A 21- to 27-year-old woman with no prior service who's 5 feet 3 inches tall is allowed to weigh up to 137 pounds. A man in the same age group who's 5 feet 8 inches tall can weigh up to 186 pounds.
Horton said the idea is to change the way recruits think about getting healthy and fit, because "being overweight means you're being overwhelmed."
And his concerns are backed up by alarming statistics.
More than 9 million young adults -- 27 percent of all Americans age 17 to 24 -- are too overweight to join the military, according to a report released in April by a group of retired admirals, generals and other senior military leaders known as "Mission: Readiness."
"Being overweight or obese turns out to be the leading medical reason why applicants fail to qualify for military service," according to the group's report, "Too Fat to Fight."
Retired Army Gen. John Shalikashvili -- a former chairman of the Joint Chiefs of Staff -- said in the report: "Every month hundreds of otherwise excellent candidates for military service are turned away by recruiters because of weight problems."
He added that since 1995, the proportion of recruits who failed their physical exams because they were overweight rose by nearly 70 percent.
"We need to reverse this trend, and an excellent place to start is by improving the quality of food served in our schools."
The group is calling on Congress to pass new child nutrition legislation that would get junk food out of schools, among other things.
One military academy seems to be taking a cue from the group. The Naval Academy is taking on the obesity fight by installing healthy-option vending machines on its Annapolis, Maryland, campus. The machines, according to the Baltimore Sun, will offer a variety of vegetables and fruit along with organic and all-natural products.
As for current members of the military, the Defense Department spends $1 billion a year on weight-related health care, according to estimates.
The Pentagon's "Medical Surveillance Monthly Report" from January 2009 found that 61 percent of men and 39 percent of women serving on active duty were overweight. In addition, 12 percent of those serving were obese, up from less than 5 percent in 1995.
The study indicated that stress and return from deployment were the most frequently cited reasons for recent weight gain.
In an effort to ensure the armed forces have a "military appearance," the Defense Department mandates that each branch of the military implement "body composition programs," including "enforcement of weight-for-height standards required for accession and advancement."
"Despite physical fitness and body fat standards, many active service members receive clinical diagnoses of overweight during routine medical examinations and other outpatient encounters," according to the MSMR.
The report documented trends from outpatient medical exams for overweight and obesity among the military during the past 11 years -- from January 1998 to December 2008.
CNN's Madison Park contributed to this report.