"It's not drug abuse, it's not asthma, it's not flat feet," said retired US Air Force Lt. Gen. Norman Seip at a Washington news conference.
So what is it?
Obesity.
According to a group of retired military officers the high numbers of overweight Americans is a "national security threat."
An estimated nine million young adults, or 27 percent of all Americans ages 17 to 24, are "too fat to fight" in the US military.
Obesity and lack of physical fitness has become one of the greatest problems the military is facing today in its efforts to recruit the next generation of soldiers, they said.
In response, officers are advocating for the passage of a wide-ranging nutrition bill that aims to make the nation's school lunches healthier and to restore or improve physical education curriculums in the nation's public schools.
The officers' group "Mission: Readiness" appeared on Capitol Hill on Tuesday to stress the need for fitter fighters.
This included retired Navy Rear Adm. James Barnett, who stressed that the obesity trend could affect recruitment goals.
"When over a quarter of young adults too fat to fight, we need to take notice," said Barnett said, adding that national security in 2030 is "absolutely dependent" on reversing childhood obesity rates.
And recruitment isn't the only problem posed by obesity. According to the report, the effects of this trend are also impacting the military, as millions of dollars are being spent every year for the replacement of service members discharged on the basis of their size and inability to pass routine military physical-fitness tests.
It is ironic that during World War II, the military had the opposite problem when many recruits who grew up in poverty during the Great Depression had to be rejected because of ill health due to malnutrition.
In fact, in 1946 the "National School Lunch Program" was pushed through Congress with the strong support of the Defense Department.
Today, the military group is urging Congress to eliminate junk food and high-calorie beverages from schools, put more money into the school lunch program and develop new strategies that help children develop healthier eating and exercise habits.
"The logic is pretty obvious," said retired Army Brig. Gen. Clara Adams-Ender. "The troops need to be in excellent physical condition because of the demands of the important jobs they do in defense. Rigorous physical and mental standards are critical if we are to maintain the fighting readiness of our military."
Even comedians are making fun of Americans' love of fast food. Speaking about the announcement this month Kentucky Fried Chicken, or KFC, introduced the "Double-Down Sandwich" which consists of bacon, cheese and mayonnaise between two slabs of fried chicken.
A late night talk show host asked his audience: "Do you want fries or a defibrillator with that?"
