Obese Boy Scouts are being screened out from competing at the 2013 National Scout Jamboree.

Held every four years, the jamboree is a 10-day gathering of thousands of scouts who camp, utilize their skills and go on adventure activities together in the great outdoors. The 2013 Jamboree will be held on 10,000 acres in the New River Gorge region of West Virginia.

Organizers have warned that activities will be particularly rough in this landscape. They will be unable to use buses and other personal vehicles. Most things will be done “on foot.”

For the first time, Scouts with a body mass index in the obese range are not allowed to participate. BMI is a measurement of height and weight used to indicate the “body fatness for most people,” according to the Centers for Disease Control and Prevention. In 2010, the CDC reported that one-third of American kids are overweight.

A BMI of 30 or more indicates obesity, the Boy Scouts said. Any child with a BMI of 30 or more will have to get a doctor’s recommendation for clearance. Any child with a BMI of 40 or more will be excluded from the 2013 Jamboree.

“It is essential that all participants and staff are prepared for their Summit jamboree experience,” said Boy Scouts of America on its website. “Our goal is to prevent any serious health-related event from occurring, and ensuring that all of our participants and staff are ‘physically strong.’”

Organizers have planned activities like mountain biking, climbing, rappelling, rafting and skateboarding, which they fear obese Scouts would not be able to do.

Boy Scouts spokesman Deron Smith said that leaders and scouts who did not fit the requirement did not apply to the Jamboree, and he is unaware of how many were affected by the new health rules.

Sources: NBC, Inquistr