A systematic review of the effectiveness of taxes on nonalcoholic beverages and high-in-fat foods as a means to prevent obesity trends.

Background: As part of the efforts to curb obesity, a new focus seems to be put on taxing foods that are perceived as being associated with obesity (eg, sugar-sweetened beverages and foods high in fat, sugar, and salt content) as a policy instrument to promote healthier diets.

Objective: To assess the possible effects of such taxation policies by identifying and analyzing all studies which investigate the impact of price increases on consumption, caloric intake, or weight outcomes.

Methods: Electronic data bases were searched with appropriate terms and their combinations. Thereafter, abstracts were reviewed and studies were selected based on predefined criteria. The characteristics of the selected studies and the results were extracted in a special form and consequently were reviewed and synthesized.

Results: Price increase may lead to a reduction in consumption of the targeted products, but the subsequent effect on caloric intake may be much smaller. Only a limited number of the identified studies reported weight outcomes, most of which are either insignificant or very small in magnitude to make any improvement in public health.

Conclusion: The effectiveness of a taxation policy to curb obesity is doubtful and available evidence in most studies is not very straightforward due to the multiple complexities in consumer behavior and the underling substitution effects. There is need to investigate in-depth the potential underlying mechanisms and the relationship between price-increase policies, obesity, and public health outcomes.