A Meta-Analysis of Food Labeling Effects on Consumer Diet Behaviors and Industry Practices

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Evidence acquisition

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. Ten databases were searched in 2014 for studies published after 1990 evaluating food labeling and consumer purchases/orders, intakes, metabolic risk factors, and industry responses. Data extractions were performed independently and in duplicate. Studies were pooled using inverse-variance random effects meta-analysis. Heterogeneity was explored with I2, stratified analyses, and meta-regression; and publication bias was assessed with funnel plots, Begg’s tests, and Egger’s tests. Analyses were completed in 2017.

Evidence synthesis

From 6,232 articles, a total of 60 studies were identified, including 2 million observations across 111 intervention arms in 11 countries. Food labeling decreased consumer intakes of energy by 6.6% (95% CI= –8.8%, –4.4%, n=31), total fat by 10.6% (95% CI= –17.7%, –3.5%, n=13), and other unhealthy dietary options by 13.0% (95% CI= –25.7%, –0.2%, n=16), while increasing vegetable consumption by 13.5% (95% CI=2.4%, 24.6%, n=5). Evaluating industry responses, labeling decreased product contents of sodium by 8.9% (95% CI= –17.3%, –0.6%, n=4) and artificial trans fat by 64.3% (95% CI= –91.1%, –37.5%, n=3). No significant heterogeneity was identified by label placement or type, duration, labeled product, region, population, voluntary or legislative approaches, combined intervention components, study design, or quality. Evidence for publication bias was not identified.

Conclusions

From reviewing 60 intervention studies, food labeling reduces consumer dietary intake of selected nutrients and influences industry practices to reduce product contents of sodium and artificial trans fat.