The portion of the force deemed obese is the percentage with a body mass index (BMI) at or above 30 kg/m 2 . As a group, military members are still far less obese than America's overall adult population—more than one-third (36.5%) of the general public is obese, according to the CDC. However, the rate of the miltary force that is obese has climbed steadily since 2001, when it was just 1.6%.

A report finds the nation’s obesity crisis now extends to the men and women who defend it, with 7.8% of total military force now classified as obese. The figure, based on data released by the Department of Defense, appeared Sunday in the Military Times .

Data show the obesity rate varies by job type; there is less obesity among combat troops (6.7%) than among healthcare workers (9.8%). Obesity is also more prevalent among women (10.3%) and minority members, as well as older service members.

But the report also found that the gender gap is shrinking. And, quoting a report from a nonprofit group of 600 retired military officers, the report found obesity and poor fitness are top reasons that most American teenagers are not eligible for military service.

Sources in the Military Times report offered a number of explanations for the obesity trend, from American youth being less active to the nature of military life itself since September 11, 2001. Wars in Iraq and Afghanistan have made operations less focused on fitness drills and more on walking over rough terrain, which some experts said build muscle but don’t help service members stay lean. The quality of food offered in the chow halls was blamed, too.

Others noted that the fact that service members remain far less obese than the general population is a good sign. In 2001, when the US Surgeon General issued a “Call to Action” to combat obesity, only 21 states had rates at 20% or higher, and no state was above 30%. Today, the most recent CDC data show no state has a rate below 20%. In addition, many of the Deep South states, where the military tradition is the strongest, have some of highest adult obesity rates.

Inside and outside the military, use of BMI to evaluate fitness has been heavily criticized. At best, critics say, it is a screening tool that demands follow-up to further evaluate a person’s overall health and fitness. People of Asian descent, in particular, have been shown to have unhealthy levels of body fat at much lower BMI levels, and some world-class athletes can be very healthy at a high BMI.

According to the report, current policy requires service members to maintain body fat levels below 28% for men and 36% for women. Failure to do so can impact future promotions and result in early separation from the service. The military plans a new system for evaluating health and fitness in service members that will be published later this year.