Over the decades, the United States armed forces have taken on and conquered some mighty foes: redcoats, Nazis, Saddam Hussein. Now they have sighted a new enemy, and it is fat.

At a time when critics question the military's readiness in this unpredictable post-Cold War world, the Pentagon has launched a campaign to improve the physical fitness of the nation's 1.4 million soldiers, sailors, airmen and marines. Goodbye Operation Desert Storm. Hello Operation Be Fit.Of course, the men and women of the military are almost certainly the most fit in America. Still, it is possible to visit the nation's bases and spot a few more paunches, saddlebags and double chins. And as for the Pentagon itself, let's just say the bureaucracy isn't the only thing that could use some trimming.

"There are military members who are very, very physically fit," said Carolyn Becraft, deputy assistant secretary of defense for personnel support, families and education. "And there are others who are not."

Bulging bellies have not exactly replaced communism in the annals of the Pentagon fears. But the issue of out-of-shape or overweight troops is serious enough to spur some of its senior strategists into action.

The effort is largely a public awareness campaign by the Department of Defense, although it calls on the Army, Navy, Air Force and Marine Corps to improve and expand sports and recreational programs and fitness centers, some of which date from World War II and before.

Last month, the Department of Defense unveiled Operation Be Fit's logo, which has an inverted Nike-like swoosh. Perhaps it is a measure of the Pentagon's bloated bureaucracy that it has taken a year from the operation's announcement to get the plans off the ground and to select the logo.

In addition, each of the services is toughening standards for physical examinations, which the troops in the Army, Navy and Marine Corps must pass twice a year, and once a year in the Air Force. Under the Army's new standards, which take effect in October, soldiers have to complete specified numbers of push-ups and sit-ups within two minutes and run two miles in a certain amount of time, which varies by age and sex.

To meet the Army's minimum standards, a 17- to 21-year-old male would have to complete 35 push-ups and 47 sit-ups and run the two miles in 16 minutes, 36 seconds (compared to 32, 35 and 16 minutes, 54 seconds, even under the old standards).