(CNN) -- Hiking! Zip-lining! Rock climbing! About 30,000 Boy Scouts and 7,000 adults are out in the mountains of southern West Virginia for the National Scouts Jamboree -- and they all had to meet a body mass index cut-off.
The Boy Scouts of America mandated that no one -- adult or child -- with a BMI of 40 or above could be accepted into the Jamboree, which is taking place July 15-24. This standard is not new; it was in place for the last jamboree as well, said Deron Smith, director of public relations for Boy Scouts of America.
"This policy is not meant to keep anyone out at all, and it's just to make sure that they're safe," Smith said. "We offer thousands of summer camp experiences (that) do not have this requirement."
The Boy Scouts' healthy living initiative has inspired children and adults alike to lose weight, Smith said. The association is encouraging people to live a healthy lifestyle.
But that's not how some see it.
The National Association to Advance Fat Acceptance, a nonprofit organization, has come out against the Boy Scouts' BMI policy, saying that the organization "believes that this decision promotes bias and negative attitudes and furthers the discrimination against boys of larger body size."
The organization publicly demanded in a statement that the Boy Scouts "reconsider their discriminatory practices and admit camp attendees NOT based on their physical fitness, NOT based on their body size, but based on their active status as a boy scout."
Most who could not meet the BMI requirement chose not to apply, Smith said. The organization does not know the number of children impacted. The Boy Scouts have not received any reactions from parents on the BMI issue, he said.
For prospective participants who have a slightly lower BMI than 40, but are still obese, there are also special requirements for the jamboree, according to the Boy Scouts' website. The jamboree's medical staff needs a health history, health data and a recommendation from a personal health care provider for children with a BMI between 32 and 39.9, which the Centers for Disease Control and Prevention considers to be in the "obese" range.
Even if the personal health care provider says there aren't any contraindications for participating, that doesn't necessarily mean a person in this BMI range will be able to participate in the whole program, the Boy Scouts' website says.
People with a BMI of 31.9 or less need a medical recommendation, too, but don't receive the additional health scrutiny.
Dr. Jennifer Shu, a pediatrician in Atlanta and CNN's Living Well expert, said she found the restrictions on children with a BMI of over 40 to be somewhat discriminatory.
"Any organization can make their own rules, but as a pediatrician I feel like we should be promoting physical activity for everybody, be as inclusive as possible, and only exclude from activity if there's a physical threat to their health," she said.
On the other hand, she noted that in some summer programs there are physical activities involving equipment that has a weight or size limit for safety reasons. That should be a restrictive factor for those particular activities, she said, because of the danger to a participant who doesn't meet the requirements.
BMI is not a perfect indicator of health and fitness; a BMI of 40 means that the person's weight is much higher than average for his or her height. Muscle can elevate BMI, so some fit people have higher BMIs than normal.
A BMI as high as 40 is unlikely to be mostly muscle, Shu said, but if there are health issues preventing that person from participating, she believes a doctor should determine that, rather than an organization making a blanket requirement.
Shu doesn't look at BMI alone when filling out medical forms for children to participate in summer programs. In addition to evaluating the kids' health, she asks children how they perceive their own abilities in specific activities, such as rock climbing, and doesn't give permission for anything with which the child doesn't feel comfortable.
The focus of the jamboree is not on the health requirements, Smith said.
"Our motto is: Be prepared," Smith said. "We're the Boy Scouts. We've been preparing our participants for years for this."
Shu offered a different perspective: "In general, we'd like to encourage physical activity for everybody." In her view, that's something the Scouts are not honoring.