Obesity in children

Last reviewed: 1 Nov 2023

Last updated: 10 Nov 2023

Obesity in children has increased in recent decades. Causes are multifactorial including biologic, genetic disposition, behavioral and environmental influences.

Calculating body mass index (BMI) is the most widely accepted method of screening for obesity in children. Abnormal BMI cutoffs in children are determined by age- and sex-specific percentiles.

Impaired glucose tolerance and type 2 diabetes mellitus are prevalent in children with obesity.

Preventing excessive weight gain in children is of paramount importance in confronting the obesity epidemic, as obesity is difficult to treat at all ages, and children with obesity tend to become obese adults.

The cornerstone of treatment is lifestyle modification including dietary modification and physical activity. Pharmacotherapy and metabolic/bariatric surgery may be considered as an adjunct to lifestyle modification in youth with severe obesity.

Definition

Obesity is a condition of excessive body fat or adiposity that exceeds healthy limits.

The most widely accepted method to screen for excess adiposity is calculation of body mass index (BMI).[1] In the US, abnormal BMI cutoffs in children are determined by age- and sex-specific percentiles based on the Centers for Disease Control and Prevention 2000 growth charts, as the amount of body fat changes with age and differs between boys and girls.[2]

An age- and sex-adjusted BMI between the 85th and 94th percentiles is defined as overweight, and a BMI ≥95th percentile (or ≥ to 30 kg/m², which ever is lower) is defined as obesity.[3][4] Severe obesity is defined as BMI of 120% of the 95th percentile.[5][6] For children ages <2 years, BMI normative values are not available. Weight-for-height values above the 95th percentile in this age group can be categorized as overweight.[7]

The World Health Organization 2006 growth standard is recommended in many countries for children ages 0-5 years, and for children ages 0-2 years in the US. WHO: Child growth standards. Opens in new window

History and exam

Key diagnostic factors

body mass index (BMI) ≥95th percentile
weight ≥95th percentile for height

More key diagnostic factors

Other diagnostic factors

increased waist-hip ratio
hypertension

Other diagnostic factors

Risk factors

obese parents
rapid weight gain in infancy
weight gain in early childhood
non-Hispanic black or Hispanic ethnicity
poor socioeconomic status
sedentary lifestyle
intrauterine growth restriction
maternal gestational diabetes
diet high in energy-dense foods, fast foods, and high-sugar beverages
screen time >2-3 hours/day
sleep deprivation
exposure to corticosteroids, antibiotics, or acid-suppressing medication
urban environment
maternal smoking in pregnancy
maternal consumption of ultra-processed foods

More risk factors

Diagnostic investigations

Investigations to consider

fasting blood glucose
serum lipids
liver function tests

More investigations to consider

Emerging tests

DEXA
bioelectric impedance analysis
abdominal CT or MRI

Treatment algorithm

ONGOING

body mass index (BMI) ≥85th to 94th percentile (overweight)

body mass index (BMI) ≥95th percentile (obesity) or BMI ≥120% of 95th percentile (severe obesity)

Contributors

Authors

Dianne Deplewski, MD

Associate Professor of Pediatrics

Section of Adult and Pediatric Endocrinology

Program Director

Pediatric Endocrinology Fellowship Program

University of Chicago

Chicago

Disclosures

DD declares that she has no competing interests.

Acknowledgements

We would like to acknowledge our Pediatric expert panel member, Dr Michael Cabana, for his contribution to this topic. MDC declares that he has served as a consultant and editor for McGraw Hill and Elsevier.

Peer reviewers

Eric M. Bomberg, MD, MAS

Assistant Professor of Pediatrics

Associate Director for Research Informatics, Center for Pediatric Obesity Medicine

Division of Endocrinology and Center for Pediatric Obesity Medicine

University of Minnesota Medical School

Minneapolis

Disclosures

EMB declares that he has been a site principal investigator and site co-investigator for Novo Nordisk. EMB's research program is supported by the National Institutes of Health (NIH) National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

Steven S. Rothenberg, MD

Chief of Pediatric Surgery

The Mother and Child Hospital

Associate Clinical Professor of Surgery

University of Colorado

Denver

Disclosures

SSR declares that he has no competing interests.

Seema Kumar, MD

Assistant Professor of Pediatrics

Mayo Clinic

Rochester

Disclosures

SK declares that she has no competing interests.

Peter Bundred, MBBS, MD

Honorary Research Fellow

Department of Health Services Research

Institute of Psychology, Health and Society

University of Liverpool

Liverpool

Disclosures

PB declares that he has no competing interests.

Differentials
- Primary hypothyroidism
- Secondary hypothyroidism
- Cushing syndrome
More Differentials
Guidelines
- Recommendations for treatment of child and adolescent overweight and obesity
- Obesity: identification, assessment and management
More Guidelines
Patient leaflets
Weight problems in children: changing unhealthy habits
Weight problems in children: improving a child's diet
More Patient leaflets
Log in or subscribe to access all of BMJ Best Practice

Use of this content is subject to our disclaimer

Obesity in children

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

Investigations to consider

Emerging tests

Treatment algorithm

body mass index (BMI) ≥85th to 94th percentile (overweight)

body mass index (BMI) ≥95th percentile (obesity) or BMI ≥120% of 95th percentile (severe obesity)

Contributors

Authors

Dianne Deplewski, MD

Disclosures

Acknowledgements

Peer reviewers

Eric M. Bomberg, MD, MAS

Disclosures

Steven S. Rothenberg, MD

Disclosures

Seema Kumar, MD

Disclosures

Peter Bundred, MBBS, MD

Disclosures

Differentials

Guidelines

Patient leaflets

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

Log in to access all of BMJ Best Practice