A Body Shape Index (ABSI) is a validated anthropometric measure describing body shape independently of BMI and height. This study aimed to evaluate the association between ABSI and dietary quality and eating behaviours in a Mediterranean clinical population.

We conducted a cross-sectional study analysing associations between ABSI and diet/behaviour using Pearson correlations and multivariable linear regressions adjusted for age, sex and BMI.

The study took place at a Mediterranean diet-based nutrition clinic in Rome, Italy.

The sample included 1640 adult patients attending follow-up visits at the clinic. ABSI z-scores were calculated and standardised by age and sex. Weekly food intake was assessed using 7-day food diaries, and behavioural preferences were collected via structured questionnaires.

The Pearson correlation between BMI and internal z-scored ABSI (zABSI) was weak but statistically significant (r = 0·113, P < 0·0001), confirming that ABSI captures body shape independently from BMI. As expected, ABSI strongly correlated with WC (r = 0·78, P < 0·001). Playing a sport was inversely associated with zABSI (β = –0·365, P < 0·001). Nighttime eating (β = 0·237, P = 0·001), snacking between meals (β = 0·133, P = 0·014) and preference for sweet over salty foods (β = 0·025, P = 0·010) were positively associated with higher ABSI values.

In this Mediterranean clinical sample, ABSI identified behavioural and dietary correlates of body shape-related risk. Promoting physical activity and addressing nighttime eating may help improve anthropometric profiles linked to abdominal fat distribution.