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Obesity: Supporting Healthier Snack Foods and Beverages Sold or Offered as Rewards in Schools


What the CPSTF Found

About The Systematic Review

In 2013, the Agency for Healthcare Research and Quality (AHRQ) conducted a meta-analysis on the effectiveness of childhood obesity prevention programs implemented in 6 intervention settings. The CPSTF finding is based on a subset of studies from the review that focused on dietary-only approaches in schools (Wang et al., 2013; 15 studies, search period through August 2012) combined with more recent evidence (36 additional studies, search period August 2012 to January 2017).

This review was conducted on behalf of the CPSTF by a team of specialists in systematic review methods, and in research, practice, and policy related to obesity prevention and control. The 2016 findings about school interventions to prevent obesity update and replace the 2003 CPSTF findings on School-Based Programs Promoting Nutrition and Physical Activity pdf icon [PDF - 1.15 MB] and School-Based Programs to Prevent Obesity pdf icon [PDF - 679 kB].


Healthy eating during childhood is important (CDC , 1998; Dietary Guidelines Advisory Committee, 2010). Schools can play an important role in preventing obesity by providing nutritious and appealing foods and beverages (CDC, 2016a; CDC, 2011).

Summary of Results

Detailed results from the systematic review are available in the CPSTF Finding and Rationale Statement pdf icon [PDF - 1.24 MB] .

The systematic review included 13 studies with 15 study arms.

Weight-Related Outcomes

  • Prevalence of overweight/obesity – one study reported no change (1 study arm) and a significant increase in overweight/obesity prevalence (1 study arm).
  • BMI z-score – decreased (1 study with 2 study arms; results were significant in 1 arm)

Diet-Related Outcomes

  • Sugar-sweetened beverage intake – mixed outcomes (9 studies)
  • Low-nutrient food intake – favorable findings (2 studies)

Summary of Economic Evidence

An economic review of this intervention was not conducted because the CPSTF did not have enough information to determine if the intervention works.


Applicability of this intervention across different settings and populations was not assessed because the CPSTF did not have enough information to determine if the intervention works.

Evidence Gaps

The CPSTF identified several areas that have limited information. Additional research and evaluation could help answer the following questions and fill remaining gaps in the evidence base. (What are evidence gaps?)

  • Which intervention activities, competitive foods and beverages, class room celebrations, parties or special events, nonfood items as rewards, or combinations of these activities are most effective? Which activities are critical to success?
  • What are the cumulative effects of adding intervention components? Is a single component equally effective?
  • In order to increase comparability what are the “best measures” for dietary intake outcomes?
  • Do children act as agents of change by discussing changes in the school environment with parents? Do parents incorporate healthier dietary habits at home?
  • How often do schools implement interventions with fidelity? What amount of training is needed for faculty?
  • Does effectiveness vary by age group?
  • Are national, state, or local policies most effective?
  • Approximately half of the studies reported on weight outcomes; future studies should report weight-related outcomes to increase understanding of intervention effectiveness.
  • For studies reporting on milk products and alternatives to dairy, what is the fat content of these foods and beverages?
  • Do interventions lead to other health benefits such as improvements in cholesterol or blood pressure?

Study Characteristics

  • Study designs included before/after design with concurrent comparison group (2 studies), prospective cohort (1 study), repeat cross-sectional with comparison (1 study), repeat cross-sectional (3 studies), or post-test only with comparison (6 studies).
  • All studies were conducted in the United States.
  • All studies evaluated interventions conducted in schools alone.
  • Studies were implemented in elementary schools (1 study), middle schools (4 studies), high schools (5 studies), or a combination of elementary, middle, or high schools (3 studies).
  • Studies were set in urban (1 study) or a combination of urban, suburban, or rural (11 studies) settings.
  • About half of each study population was female (10 studies; 3 studies did not provide information).