What is disordered eating? And why do 20% of the world's kids show signs of it? Experts explain

Early intervention is helpful for people showing signs of both eating disorders and disordered eating, said therapist Jennifer Rollin, founder of The Eating Disorder Center in Rockville, Maryland.

This story is part of an occasional series covering disordered eating and diet culture.

(CNN)More than 1 in 5 kids and adolescents around the world show signs of disordered eating, according to a new study.

The study highlights a serious public health issue that often goes underreported and underrecognized, according to the meta-analysis published Monday in the journal JAMA Pediatrics.
Researchers reviewed and analyzed 32 studies from 16 countries and found that 22% of children and adolescents showed disordered eating behaviors. Those numbers were higher among girls, older adolescents and those with a higher body mass index, or BMI, according to the study.
    Disordered eating is similar in behavior to an eating disorder — it can include strict food rules around how much a person eats, what they are eating and how much they are exercising in relation to their food, said therapist Jennifer Rollin, founder of The Eating Disorder Center in Rockville, Maryland.
      For someone to be diagnosed with an eating disorder, there are similar symptoms along with a higher level of rigidity, distress and impairment of life function, she added. Disordered eating behaviors can progress to a person being diagnosed with an eating disorder.
        "However, it's important to note that both disordered eating and eating disorders are serious and deserve treatment and professional help," Rollin said via email.
        Disordered eating behavior may be undertreated because kids might hide their symptoms or avoid seeking help due to stigma, according to the study.
          Likewise, the study may have been limited in its ability to portray the full scope because it relied on data in which kids and adolescents self-reported their behavior, said study author Dr. José Francisco López-Gil, a postdoctoral researcher at the Health and Social Research Center at the University of Castilla-La Mancha in Spain.
          Eating disorder resources

          US: National Eating Disorder Association

          The NEDA has a confidential, toll-free helpline at 800-931-2237 as well as an online click-to-chat service. For 24/7 crisis support, text "NEDA" to 741-741.

          The NEDA also has a list of online and free or low-cost resources.

          US: National Association of Anorexia Nervosa and Associated Disorders

          ANAD runs a helpline at 888-375-7767 from 9 a.m. to 9 p.m. CT and provides links to support groups and treatment providers.

          Australia: National Eating Disorders Collaboration

          A call center at 800-334-673 and online chat run by the Butterfly Foundation is open 8 a.m. to midnight AET every day except public holidays.

          UK: Beat (formerly known as the Eating Disorders Association)

          Helplines for England, Scotland, Wales and Northern Ireland are open 9 a.m. to midnight weekdays and 4 p.m. to midnight weekends and bank holidays, every day of the year.

          "The prevalence of disordered eating could be even higher if children were asked about binge-eating or muscle-building symptoms and included studies during the pandemic," said Dr. Jason Nagata, assistant professor of pediatrics at the University of California San Francisco. Nagata was not involved in the research.
          Researchers next need to delve into what is causing the disordered eating behaviors, López-Gil said. But in the meantime, experts hope that institutions and families will focus on identifying and helping kids who are showing signs of disordered eating.
          Those kinds of behaviors are dangerous and can lead to severe medical complications to organs including the heart, brain, liver and kidneys, Nagata said.
          "Disordered eating is a significant problem among children and adolescents, and early detection and intervention are crucial to prevent long-term health consequence," López-Gil said in an email.
          "The findings can help health professionals, educators, and parents understand the magnitude of the problem and develop strategies for prevention and intervention."

          The signs of disordered eating

          Adults should be aware of signs of disordered eating in both themselves and their children, López-Gil said.