The impact of price and nutrition labelling on sugary drink purchases: Results from an experimental marketplace study.

Objective: To examine the effect of front-of-package (FOP) nutrition labelling and sugary drink taxation on consumer beverage purchases.

Methods: A total of 675 respondents aged 16 years and older participated in an experimental marketplace study using a 4 × 5 within-between group design. Participants were randomised to one of four labelling conditions (no label; star rating; high sugar symbol; health warning) and completed five within-subject purchase tasks. Beverage prices in each task corresponded to 'tax' conditions: 0%, 10%, 20%, 30% and a variable tax proportional to free sugar level. In each task, participants selected from 20 commercially available beverages; upon conclusion, one of five selections was randomly chosen for purchase.

Results: As price increased, participants were significantly less likely to select a sugary drink, and selected drinks with fewer calories and less free sugar (p < 0.001 for all). The overall effect of labelling was not statistically significant, although there was a trend for the 'high sugar' label to reduce the likelihood of selecting a sugary drink (p = 0.11) and encouraging participants to select drinks with less free sugar (p = 0.11).

Conclusions: Increasing price was associated with reduced sugary drink purchases. Enhanced FOP labelling results highlight the need for further research to investigate their potential impact. The study adds empirical support for taxation to reduce sugary drink consumption.