Adherence to a healthy plant-based diet is associated with adiposity indicators in Costa Rican adults

Plant-based diets have been associated with favourable health outcomes; however, not all plant-based diets are of the same quality. This study aimed to investigate the associations between three plant-based diet indices: overall plant-based diet index (PDI), healthy PDI (hPDI) and unhealthy PDI (uPDI) and measures of adiposity: wrist circumference, waist circumference, waist:hip ratio and BMI. This study used data from 2027 controls in the Costa Rica Heart Study, a case-control study. A validated FFQ was used to create the plant-based diet indices. Multivariable linear regression was used to examine associations between quintiles of the plant-based diet indices and adiposity indicators. Higher hPDI scores were associated with lower adiposity, with waist circumference showing the strongest association. Participants in the highest hPDI quintile had a β = -1·90 cm (95 % CI: -3·32, -0·49) lower waist circumference and a β = -0·72 kg/m² (95 % CI: -1·33, -0·10) lower BMI compared with participants in the lowest quintile. Significant linear trends were observed with waist circumference (P-trend = 0·0037), waist:hip ratio (P-trend = 0·0064) and BMI (P-trend = 0·0171). Subjects in the 5th quintile of the overall PDI had significantly lower waist circumference (β = -1·75 cm (95 % CI: -3·14, -0·36)), waist-to-hip ratio (β = -0·010 (95 % CI: -0·019, -0·001)) and BMI (β = -0·62 kg/m² (95 % CI: -1·22, -0·02)). In general, uPDI showed no significant associations with adiposity indicators. Among Costa Rican adults, adherence to hPDI is associated with lower adiposity, whereas uPDI showed no association, indicating the quality of plant-based diets plays a role in body composition.