Earlier this year, a group of retired generals released a report detailing the stunning number of military recruits who were deemed too fat to serve in the U.S. Army, singled out school lunches as a leading culprit for the trend. Now, a new study by the National Bureau of Economic Research has labeled military obesity a "potential national security threat," and another report by Cornell researchers details just how much the Army has ballooned in size over the past 50 years. Here's a quick look at how obesity may be leaving America vulnerable:

How big is too big for the Army?
It depends on age and height, but the Army generally allows female enlistees to weigh up to 241 pounds and have 36 percent body fat; for men, it's a maximum 259 pounds and 30 percent body fat.

How serious is this problem?
According to military recruiters, 48,000 would-be enlistees were rejected solely for being overweight between 2005 and 2009, and about 12,000 soldiers leave the U.S. military prematurely each year because they can't pass the annual physical fitness test. The NBER study, meanwhile, says that "from 2007 to 2008, 5.7 million men and 16.5 million women of military age were over the U.S. Army's enlistment standards for weight-for-height and body fat percentage."

Didn't we already know this?
While previous studies focused only on data from 2006 to 2008, the new Cornell study "charted the climbing obesity rates using data from the National Health and Nutrition Examination Surveys spanning 1959 to 2008," according to The Christian Science Monitor. Taking the long view of America's expanding waistline, the study found that male obesity rates have more than doubled during those 49 years, and women's obesity rates have more than tripled.

Any new ideas to solve the problem?
The Cornell study suggests the army simply lower its standards by "[easing] the height/weight ratios and body fat standards, particularly for noncombat troops." But advocacy groups are taking matters into their own hands. The Physicians Committee for Responsible Medicine wrote a letter to Joint Chief of Staff chairman Mike Mullen, "offering free copies of its 'Vegetarian Starter Kit,'" which "offers a three-step program to adopt a plant-based diet as well as tips on getting down to a healthy weight."

Is America the only country worried about obese soldiers?
No. Recent British and German reports warned that thousands of troops were too fat to deploy to Afghanistan or, if deployed, to fight effectively; the German report blamed the problem largely on excessive boozing. Chinese observers are also concerned: In March, Chinese fitness expert Yang Hua asked a parliamentary advisory board if "the younger Chinese [would] be able to fight the Japanese one-on-one," should China ever wage war on Japan.

Sources: CNN, Reuters, Frum Forum, Daily Mail, Christian Science Monitor, LA Times

This article originally ran on April 21 and was updated on October 20.