US Army soldier in Afghanistan Reuters - Shamil Zhumatov Joining the military takes more than being 18 years old and having a high school diploma.

In the U.S., you need to pass a standardized test, a criminal background check, medical requirements, and meet height and weight standards.

For both the U.S. and China, that last requirement is becoming a problem.

A recent article from the official site of China's People's Liberation Army highlights major woes with army recruitment efforts in Beijing, with many applicants deemed unsuitable due to weight problems, or shortsightedness.

According to the report, 23% failed the eye exam, while 19% were either obese, or underweight. Roughly 60% of college students applying to the PLA failed the physical fitness test.

From the report:

The office says the issue of declining fitness affecting the recruitment figures is not new. Last year's figures were also disappointing, with poor eyesight, obesity, urine abnormalities and osteoarthritis among the most prominent issues.

The issue first reached the attention of military recruiters some years ago, and steps were taken to adjust to new realities. The capital has twice lowered standards for physical fitness for those applying for military service, first in 2008 and again 2011.

"It's not possible to improve the physical condition of the students rapidly," Liu Bo of Tsinghua University told China Daily. "We have ignored the importance of exercise since childhood because of the increasing pressure to gain entry to educational institutions."

The problem has been on the minds of the U.S. military for some time — with 27% of 17- to 24-year-olds deemed too fat for military service, according to CBS.

A report prepared by Mission: Readiness, a nonpartisan group of retired military generals and admirals, lays out the problem:

"Being overweight or obese turns out to be the leading medical reason why applicants fail to qualify for military service. Today, otherwise excellent recruit prospects, some of them with generations of sterling military service in their family history, are being turned away because they are just too overweight."

Neither military is about to be destroyed by extended waistlines, but it certainly has an effect.

"You can't say it's currently crippling the U.S. military — that's not true," John Cawley, a Cornell University researcher, told The Chicago Tribune. "But it's a serious problem, and if we get in a situation that we have to rapidly expand the size of the military, then it's going to be a really seriously binding constraint."

The weight standards have gone up as the average American's weight has expanded, but a further drop in standards could have unintended consequences. A 2004 study found almost 80% of recruits who failed their first weight test were unable to complete their first term of enlistment, according to Military.com.

"The folks that are going to enter the military in 2025 are in school right now," Retired Air Force Lt. Gen. Norman Seip told Reuters. "So it's up to us to ensure that when those children reach the age of between 17 and 24 that they are ready or eligible to join the military."