WATERTOWN, Wis. -- With America at war and in need of a few good men, Jon Schoenherr expected a warm reception when he walked into an Army recruiting office in this Midwestern farm community, intending to enlist.
But a sergeant gave the 17-year-old some surprising news.
''He told me I'd have to lose a little bit of weight," said Schoenherr, who dropped 50 pounds to qualify.
Besides terrorists, germ warfare, and nuclear weapons, military officials increasingly worry about a different kind of threat -- troops who are too fat to fight.
Weight issues plague all branches of the military, from elite Marines to the Air Force. Thousands of troops are struggling to lose weight, and thousands have been booted out of the service in recent years because they couldn't.
One of the biggest worries concerns those not even in uniform yet, however: Nearly 2 out of every 10 men and 4 out of every 10 women of recruiting age weigh too much to be eligible, a record number for that age group.
''This is quickly becoming a national security issue for us. The pool of recruits is becoming smaller," said Colonel Gaston Bathalon, an Army nutrition specialist.
Unless weight rules are relaxed, he said, ''we're going to have a harder time fielding an army."
Today's soldiers are 37 pounds heavier on average than their Civil War counterparts. Military officials say that's not all bad, because most of it is muscle, not fat, and the result of better nutrition. ''Large and in charge" makes soldiers look more formidable to the enemy, they note.
But weight problems add stress to already stressful jobs, costing many soldiers promotions and leading some to try desperate measures such as rubber suits and risky pills to shed pounds.
Problems don't end when active duty does, either. The Veterans Affairs health system increasingly is treating vets piling on pounds and developing weight-related diseases like diabetes.
Ironically, the big concern used to be soldiers not weighing enough. Congress passed the school lunch program after World War II, worried that too many high schoolers were malnourished and unfit to fight.
''This is the same deal in reverse. We've got young kids who are not going to be qualified for military service; they're either unfit or overfat," said Colonel Karl Friedl, commander of the US Army Research Institute of Environmental Medicine in Natick.
In 2003 alone, more than 3,000 people were kicked out of the military for failing weight standards, Bathalon's study reports.
Efforts to change the statistic start with new recruits. Marines as much as 10 percent over weight standards can be sent to boot camp. ''The Marines say, 'Send us anybody and we'll turn them into a Marine.' They're pretty successful at it," Friedl said.