To evaluate the association between ultra-processed food consumption and adherence to the EAT-Lancet diet in a representative sample of the Brazilian population.

The study used data from the Brazilian National Dietary Survey 2017–2018 and employed linear regression models to evaluate the association between ultra-processed food consumption and adherence to the EAT-Lancet diet, as measured by the Nova food system and Planetary Health Diet Index (PHDI), respectively.

Nationally representative sample of the Brazilian population.

The study included 46 164 Brazilians ≥ 10 years old.

The average PHDI total score was 45·9 points (95 % CI 45·6, 46·1). The ultra-processed food consumption was, with dose-response, inversely associated with the adherence to the EAT-Lancet diet. The PHDI total score was 5·38 points lower (95 % CI –6·01, –4·75) in individuals in the highest quintile of consumption of ultra-processed foods, as compared to those in the first quintile. The PHDI score was also inversely associated with the share of processed culinary ingredients and processed foods and positively associated with the share of unprocessed or minimally processed foods.

Our study showed an inverse relationship between the consumption of ultra-processed foods and the adherence to a healthy and sustainable diet.