British soldiers are getting so fat it's putting lives at risk, according to a leaked memo from the army's physical training corps published in a Sunday newspaper.

The Observer said an emergency memo sent to all units of the British army earlier this month warned that an increasing number of soldiers had become so fat they couldn't be deployed to conflict zones and urged commanders to focus on physical fitness.

The army "has not consistently maintained our standards of physical fitness" and needs to "reinvigorate a warrior ethos and a culture of being fit," the newspaper quoted the July 10 memo as saying.

The Ministry of Defense offered no direct comment on The Observer's report but it did not dispute its accuracy. The ministry said only that commanders had recently been told to ensure that all units were following the army's physical fitness policy.

The newspaper said the memo warned that an increasing number of British soldiers were being classified as "personnel unfit to deploy," putting operations and lives at risk in places such as Afghanistan, where British forces are grappling with Taliban rebels in brutal conditions.

The report comes three years after Britain's military loosened its fitness requirements to reach more recruits. The maximum body mass index allowable for an enlistee was raised from 28 to 32. The World Health Organization defines "overweight" as a body mass index equal to or more than 25, and "obese" as an index equal to or more than 30.

Obesity is a growing problem in Britain, as in many other countries. In 2007 a government-commissioned report predicted that as many as nine out of 10 U.K. adults could be overweight by 2050.

Widening waistlines are a problem for the U.S. Army as well. Earlier this year the Army's recruitment chief said obesity was the biggest obstacle to enrolling young men and women into the military — more of a problem than lack of education or a criminal record.