Cochrane for Clinicians
Putting Evidence into Practice
Interventions for Reducing Childhood Obesity
Am Fam Physician. 2020 Apr 1;101(7):394.
Author disclosure: No relevant financial affiliations.
Clinical Question
Do dietary and physical activity interventions reduce obesity rates in children?
Evidence-Based Answer
Individual dietary interventions alone fail to change body mass index (BMI) or the standardized BMI z-score (zBMI) across all age groups. The impact of regular physical activity or combined dietary and physical activity interventions is modest at best.1 (Strength of Recommendation [SOR]: C, based on consensus, disease-oriented evidence, usual practice, expert opinion, or case series.)
In children five years and younger, combined dietary and physical activity interventions mildly decrease BMI and zBMI.1 (SOR: C, based on consensus, disease-oriented evidence, usual practice, expert opinion, or case series.)
In children six to 12 years of age, physical activity interventions alone mildly decrease BMI without changing zBMI, whereas combined interventions mildly decrease zBMI without changing BMI.1 (SOR: C, based on consensus, disease-oriented evidence, usual practice, expert opinion, or case series.)
In children 13 years and older, low-quality evidence shows no change in either BMI or zBMI, even when dietary and physical activity interventions are combined.1 (SOR: C, based on consensus, disease-oriented evidence, usual practice, expert opinion, or case series.)
SUMMARY TABLE
Effects of Dietary and Physical Activity Interventions on Body Mass Index and Body Mass Index Z-scores in Children 0 to 18 Years of Age
| Age group (years) | Intervention | Outcome | Difference | Studies | Participants | Evidence quality |
|---|---|---|---|---|---|---|
0 to 5 | Diet | zBMI | Not significant | 1 | 520 | Moderate |
Physical activity | zBMI/BMI | Not significant | 4/5 | 1,053/2,233 | High | |
Diet and physical activity | zBMI | MD = 0.07 lower (95% CI, 0.14 to 0.01) | 16 | 6,261 | Moderate | |
BMI | MD = 0.11 kg per m2 lower (95% CI, 0.21 to 0) | 11 | 5,536 | Moderate | ||
6 to 12 | Diet | zBMI/BMI | Not significant | 6/9 | 7,231/5,061 | High |
Physical activity | zBMI | Not significant | 8 | 6,841 | Moderate | |
BMI | MD = 0.10 kg per m2 lower (95% CI, 0.14 to 0.05) | 14 | 16,410 | Moderate | ||
Diet and physical activity | zBMI | MD = 0.05 lower (95% CI, 0.10 to 0.01) | 20 | 24,043 | Low | |
BMI | Not significant | 25 | 19,498 | Low | ||
13 to 18 | Diet | BMI | Not significant | 2 | 294 | Low |
Physical activity | zBMI | MD = 0.20 lower (95% CI, 0.30 to 0.10) | 1 | 100 | Low | |
BMI | MD = 1.53 kg per m2 lower (95% CI, 2.67 to 0.39) | 4 | 720 | Very low | ||
Diet and physical activity | zBMI/BMI | Not significant | 6/8 | 16,543/16,583 | Low |
BMI = body mass index; MD = mean difference; zBMI = body mass index z-score.
SUMMARY TABLE
Effects of Dietary and Physical Activity Interventions on Body Mass Index and Body Mass Index Z-scores in Children 0 to 18 Years of Age
| Age group (years) | Intervention | Outcome | Difference | Studies | Participants | Evidence quality |
|---|---|---|---|---|---|---|
0 to 5 | Diet | zBMI | Not significant | 1 | 520 | Moderate |
Physical activity | zBMI/BMI | Not significant | 4/5 | 1,053/2,233 | High | |
Diet and physical activity | zBMI | MD = 0.07 lower (95% CI, 0.14 to 0.01) | 16 | 6,261 | Moderate | |
BMI | MD = 0.11 kg per m2 lower (95% CI, 0.21 to 0) | 11 | 5,536 | Moderate | ||
6 to 12 | Diet | zBMI/BMI | Not significant | 6/9 | 7,231/5,061 | High |
Physical activity | zBMI | Not significant | 8 | 6,841 | Moderate | |
BMI | MD = 0.10 kg per m2 lower (95% CI, 0.14 to 0.05) | 14 | 16,410 | Moderate | ||
Diet and physical activity | zBMI | MD = 0.05 lower (95% CI, 0.10 to 0.01) | 20 | 24,043 | Low | |
BMI | Not significant | 25 | 19,498 | Low | ||
13 to 18 | Diet | BMI | Not significant | 2 | 294 | Low |
Physical activity | zBMI | MD = 0.20 lower (95% CI, 0.30 to 0.10) | 1 | 100 | Low | |
BMI | MD = 1.53 kg per m2 lower (95% CI, 2.67 to 0.39) | 4 | 720 | Very low | ||
Diet and physical activity | zBMI/BMI | Not significant | 6/8 | 16,543/16,583 | Low |
BMI = body mass index; MD = mean difference; zBMI = body mass index z-score.
Practice Pointers
Obesity in children is defined as a BMI at the 95th percentile or greater on growth charts from the Centers for Disease Control and Prevention (CDC). Childhood obesity rates are increasing, affecting 14% of children in 1999 and 19% in 2016.2 Obesity rates in low- and middle-income families are nearly double those in high-income families.2 Obesity rates among Hispanic and black children are more than double those in Asian children and nearly double those in non-Hispanic white children.2 The authors of this review sought to characterize the effect of lifestyle interventions to prevent childhood obesity in different age ranges.
This Cochrane review included 153 randomized controlled trials with 51,946 patients.1 Studies were heterogeneous in population, interventions, and duration. Nearly 90% of studies were from the United States and Europe, and more than 60% of studies evaluated a combination of dietary and physical activity interventions. More than one-half were conducted in school or day care settings, 14% of which had a family component, and 9% were conducted in homes. Populations studied varied from all children to only overweight or obese children. Interventions included education, health promotion, and family or behavioral therapy. Studies were conducted for a minimum of three months with only 24% of studies exceeding 12 months and only 8% exceeding two years. No adverse effects, including an increased rate of underweight children, were r
References
show all references1. Brown T, Moore TH, Hooper L, et al. Interventions for preventing obesity in children. Cochrane Database Syst Rev. 2019;(7):CD001871....
2. Centers for Disease Control and Prevention. Childhood obesity facts. October 2017. Accessed August 26, 2019. https://www.cdc.gov/obesity/data/childhood.html
3. Centers for Disease Control and Prevention. Modified z-scores in the CDC growth charts. 2016. Accessed October 7, 2019. https://www.cdc.gov/nccdphp/dnpa/growthcharts/resources/BIV-cutoffs.pdf
4. 2018 Physical Activity Guidelines Advisory Committee. 2018 Physical Activity Guidelines Advisory Committee scientific report. Department of Health and Human Services; 2018. Accessed July 30, 2019. https://health.gov/our-work/physical-activity/current-guidelines/scientific-report
5. National Institute for Health and Care Excellence (NICE). Obesity: identification, assessment and management. Clinical guideline 189. November 2014. Accessed August 25, 2019. https://www.nice.org.uk/guidance/cg189.
These are summaries of reviews from the Cochrane Library.
This series is coordinated by Corey D. Fogleman, MD, assistant medical editor.
A collection of Cochrane for Clinicians published in AFP is available at https://www.aafp.org/afp/cochrane.
Copyright © 2020 by the American Academy of Family Physicians.
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