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 behaviors in a Mediterranean clinical population.

We conducted a cross-sectional study analyzing associations between ABSI and diet/behavior 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 1,640 adult patients attending follow-up visits at the clinic. ABSI z-scores were calculated and standardized by age and sex. Weekly food intake was assessed using 7-day food diaries, and behavioral preferences were collected via structured questionnaires.

The Pearson correlation between BMI and internal 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 waist circumference (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 behavioral 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.