Arterialized venous serum insulin concentrations pre-1 week and post-1 week of forearm immobilization in healthy young men fed an A, eucaloric control diet (CON; n = 11) or a B, high-fat overfeeding diet (HFD; n = 9) providing 50% excess energy from fat in the postabsorptive state (0 minutes) and for a 3-hour postprandial period following the ingestion of a mixed meal. CON and HFD data were compared within the same statistical test (3-way analysis of variance with immobilization, time, and diet as factors). Significant main effects of immobilization (ie, pre vs post; P < .05) and time (ie, response to mixed meal ingestion; P < .001) were observed, with no effects of diet (P = .29) or any interactions (all P > .05).