Efeito das recomendações de troca de alimentos sobre a saúde e a pegada de carbono das compras de mercearia em uma loja online naturalista: Um ensaio paralelo randomizado

O que aconteceu

Estudos de modelagem sugerem que simples "swaps" dietéticos em que apenas um alimento é substituído por outro poderia produzir benefícios tanto para a saúde quanto para o meio ambiente, mas permanece incerto se os consumidores fazem tais mudanças quando solicitados. Testamos se a recomendação de swaps melhorou a saúde e reduziu a pegada de carbono de seleções de mercearia online simuladas. ClinicalTrials.gov (NCT#06648226), submetido pela primeira vez em 16 de outubro de 2024.

O que encontraram

In May-June 2025, we recruited 1,201 US adults ages 18+ for a randomized parallel trial. Participants completed 3 weekly study visits. In the first visit, participants shopped in a naturalistic online grocery store with no intervention. They were then randomized in parallel to 1 of 4 trial arms: (1) climate swaps (n = 301), (2) health swaps (n = 300), (3) climate + health swaps (n = 300), or (4) control (n = 300). In the second and third visits, participants completed the shopping task in their randomly assigned trial arm. Participants were not masked to their trial arm. Using intent-to-treat analyses, we assessed 2 primary endpoints: the healthfulness (operationalized as the average Ofcom Nutrient Profiling Model score across the selected items [range: 1-100]) and carbon footprint (operationalized as the average kg of carbon dioxide equivalents [CO2-eq] per kg associated with producing the selected items) of participants' grocery selections. We examined whether outcomes changed from the first (no-intervention) visit to the second and third (intervention) visits in the swaps arms compared to the control arm. The climate (B = 2.4 on the 1-100 scale, 95% CI [1.1, 3.7]), health (B = 4.7, 95% CI [3.3, 6.0]), and climate + health (B = 4.0, 95% CI [2.7, 5.4]) swaps each improved the healthfulness of participants' selections compared to control (all ps < 0.001). The health and climate + health swaps both increased healthfulness more than the climate swaps (ps ≤ 0.02) but did not differ from one another (p = 0.34). The climate (B = -3.3 kg CO2-eq per kg, 95% CI [-4.6, -2.1]; p < 0.001) and climate + health swaps (B = -2.8, 95% CI [-4.1, -1.6]; p < 0.001), but not the health swaps (B = -0.4, 95% CI [-1.7, 0.8]; p = 0.51), reduced the carbon footprint of participants' selections compared to control. The climate and climate + health swaps led to larger reductions in carbon footprint than the health swaps (ps < 0.001) but did not differ from one another (p = 0.43). Swaps' effects on healthfulness and carbon footprint did not differ by age, health consciousness, or environmental consciousness (ps for interactions ≥0.10). The main limitations were that the sample differed somewhat from the US population and study results may not generalize to brick-and-mortar stores.

Trecho mantido em inglês: a tradução automática não passou na conferência de números.

Por que isso importa

Incentivar as trocas para alimentos mais saudáveis e com baixo teor de carbono melhorou a saúde e reduziu a pegada de carbono das seleções de mercearia online.