Greater Trunk but Comparable Arm Circumference Reductions With 16:8 Intermittent Fasting Versus 10% Caloric Restriction: An 8-Week Experimental Study in Indian Adults

Abstract

This study compared regional anthropometric responses to a 16:8 intermittent fasting (IF) protocol and a traditional 10% calorie-restricted diet (CRD) in Indian adults with elevated adiposity. Sixty participants were randomly allocated to IF (n = 30) or CRD (n = 30) for eight weeks. Waist, hip, chest, left bicep, and right bicep circumferences were assessed at baseline, four weeks, and eight weeks using a non-elastic anthropometric tape. A 2 × 3 mixed ANOVA tested Time, Group, and Time × Group effects. The IF group showed larger pre-to-post reductions in waist circumference (6.53 cm vs. 2.92 cm), hip circumference (6.62 cm vs. 2.71 cm), and chest circumference (5.12 cm vs. 2.37 cm). Significant Time × Group interactions were observed for waist, F(1.019, 59.100) = 111.963, p < .001, η²p = .659; hip, F(1.007, 58.394) = 132.671, p < .001, η²p = .696; and chest circumference, F(1.006, 58.358) = 95.156, p < .001, η²p = .621. In contrast, the interaction was not significant for left bicep, F(1.236, 71.674) = 1.455, p = .237, η²p = .024, or right bicep circumference, F(1.257, 72.927) = 1.855, p = .176, η²p = .031. These findings indicate a regional pattern in which 16:8 IF produced substantially greater reductions at trunk sites while arm-girth changes were comparable between dietary strategies.