Plant-based diet adherence is associated with metabolic health status in adults living with and without obesity

Purpose: Metabolic health phenotypes exist across the body mass index spectrum. Diet may be an important modifiable risk factor, yet limited research exists on dietary patterns in this context. We investigated associations between dietary patterns, reflecting dietary quality, healthfulness and inflammatory potential, and metabolic health phenotypes in adults living with and without obesity. Methods: This cross-sectional study included 2,040 middle- to older-aged men and women randomly selected from a large primary care centre. The Dietary Approaches to Stop Hypertension score, Healthy Eating Index, Dietary Inflammatory Index, overall, healthful and unhealthful plant-based dietary indices and Nutri-Score were derived from validated food frequency questionnaires. Descriptive and logistic regression analyses were used to examine diet score relationships with metabolic health phenotypes (Metabolically Healthy/Unhealthy Obese (MHO/MUO) and Non-Obese (MHNO/MUNO)), defined using three separate metabolic health definitions, each capturing different aspects of metabolic health. Results: In fully adjusted models, higher unhealthful plant-based dietary scores were associated with a lower likelihood of MHO (OR = 0.96, 95% CI: 0.93–1.00, p = 0.038) and MHNO (OR = 0.97, 95% CI: 0.95–0.99, p = 0.006). Higher Nutri-Score values were associated with an increased likelihood of MHNO (OR = 1.06, 95% CI: 1.01–1.13, p = 0.033). Conclusion: These findings provide evidence that more unhealthful plant-based diets may be linked with unfavourable metabolic health status, irrespective of BMI.