A, Forearm muscle anatomical cross-sectional area (aCSA) and B, maximal grip strength pre-1 week and post-1 week of forearm immobilization in the nonimmobilized (free) and immobilized (immob) arms of healthy young men fed a eucaloric control diet (CON; n = 11) or a high-fat overfeeding diet (HFD; n = 9) providing 50% excess energy from fat. CON and HFD data were compared within the same statistical test (3-way analysis of variance with arm, immobilization, and diet as factors). For muscle aCSA, a significant main effect of arm (ie, free vs immobilized; P < .001; denoted by *), but no effects of immobilization (ie, pre vs post; P = .60), diet (P = .95), or any interactions (all P > .05) were observed. For maximal grip strength, significant main effects of arm (P < .001; denoted by *) and immobilization (P < .001), and an immobilization × arm interaction (P < .001) were observed, with no effect of diet (P = .72) or any other interactions (all P > .05) observed. $Denotes significantly different from corresponding pre value.