Associations of EAT-Lancet Planetary Health Diet or Finnish Nutrition Recommendations with changes in obesity measures: a follow-up study in adults

Background: Knowledge on the association between the EAT-Lancet Planetary Health Diet (PHD) or the Finnish Nutrition recommendations (FNR) and anthropometric changes is scarce. Especially, the role of the overall diet quality, distinct from energy intake, on weight changes needs further examination. Objectives: To examine the association between diet quality and weight change indicators and to develop a dietary index based on the PHD adapted for the Finnish food culture. Methods: The study population consisted of participants of two Finnish population-based studies (n = 4,371, 56% of women, aged 30−74 years at baseline). Dietary habits at the baseline were assessed with a validated food frequency questionnaire including 128−130 food items. We developed a Planetary Health Diet Score (PHDS) (including 13 components) and updated the pre-existing Recommended Finnish Diet Score (uRFDS) (including nine components) with energy density values to measure overall diet quality. Weight, height, and waist circumference (WC), and the body mass index (BMI) were measured at the baseline and follow-up, and their percentual changes during a 7-year follow-up were calculated. Two-staged random effects linear regression was used to evaluate β-estimates with 95% confidence intervals. Results: Adherence to both indices was relatively low (PHDS: mean 3.6 points (standard deviation [SD] 1.2) in the range of 0−13; uRFDS: mean 12.7 points (SD 3.9) in the range of 0−27). We did not find statistically significant associations between either of the dietary indices and anthropometric changes during the follow-up (PHDS, weight: β −0.04 (95% CI −0.19, 0.11), BMI: β 0.05 (−0.20, 0.10), WC: β −0.08 (−0.22, 0.06); uRFDS, weight: β 0.01 (−0.04, 0.06), BMI: β 0.01 (−0.04, 0.06), WC: β −0.02 (−0.07, 0.03)). Conclusion: No associations between overall diet quality and anthropometric changes were found, which may be at least partly explained by low adherence to the PHD and the FNR in the Finnish adult population.