The effects of health-related food taxes on the environmental impact of consumer food purchases: secondary analysis of data from a randomised controlled trial in a virtual supermarket.

ABSTRACT

OBJECTIVE: To measure the effects of health-related food taxes on the environmental impact of consumer food purchases in a virtual supermarket. DESIGN: This is a secondary analysis of data from a randomised controlled trial in which participants were randomly assigned to a control condition with regular food prices (n 152), an experimental condition with a sugar-sweetened beverage (SSB) tax (n 131) or an experimental condition with a nutrient profiling tax based on Nutri-Score (n 112). Participants were instructed to undertake their typical weekly grocery shopping for their households. Primary outcome measures were three environmental impact indicators greenhouse gas (GHG) emissions, land use and blue water use per household per week. Data were analysed using linear regression analyses. SETTING: Three-dimensional virtual supermarket. PARTICIPANTS: Dutch adults (≥ 18 years) who were responsible for grocery shopping in their household (n 395). RESULTS: GHG emissions (-7·6 kg CO2-eq; 95 % CI -12·7, -2·5) and land use (-3·9 m2/year; 95 % CI -7·7, -0·2) were lower for the food purchases of participants in the nutrient profiling tax condition than for those in the control condition. Blue water use was not affected by the nutrient profiling tax. Moreover, the SSB tax had no significant effect on any of the environmental impact indicators. CONCLUSIONS: A nutrient profiling tax based on Nutri-Score reduced the environmental impact of consumer food purchases. An SSB tax did not affect the environmental impact in this study.