The effects of a sugar-sweetened beverage tax and a nutrient profiling tax based on Nutri-Score on consumer food purchases in a virtual supermarket: a randomised controlled trial

OBJECTIVE: To investigate the effects of a sugar-sweetened beverage (SSB) tax and a nutrient profiling tax on consumer food purchases in a virtual supermarket. DESIGN: A randomised controlled trial was conducted with a control condition with regular food prices (n 152), an SSB tax condition (n 130) and a nutrient profiling tax condition based on Nutri-Score (n 112). Participants completed a weekly grocery shop for their household. Primary outcome measures were SSB purchases (ordinal variable) and the overall healthiness of the total shopping basket (proportion of total unit food items classified as healthy). The secondary outcome measure was the energy (kcal) content of the total shopping basket. Data were analysed using regression analyses. SETTING: Three-dimensional virtual supermarket. PARTICIPANTS: Dutch adults aged ≥18 years are being responsible for grocery shopping in their household (n 394). RESULTS: The SSB tax (OR = 1·62, (95 % CI 1·03, 2·54)) and the nutrient profiling tax (OR = 1·88, (95 %CI 1·17, 3·02)) increased the likelihood of being in a lower-level category of SSB purchases. The overall healthiness of the total shopping basket was higher (+2·7 percent point, (95 % CI 0·1, 5·3)), and the energy content was lower (−3301 kcal, (95 % CI −6425, −177)) for participants in the nutrient profiling tax condition than for those in the control condition. The SSB tax did not affect the overall healthiness and energy content of the total shopping basket (P > 0·05). CONCLUSIONS: A nutrient profiling tax targeting a wide range of foods and beverages with a low nutritional quality seems to have larger beneficial effects on consumer food purchases than taxation of SSB alone.