In contrast, in the VAT of the Ob + NGT and Ob + Pre-T2D groups, GIP (1 nM) stimulation decreased lactate production (Ob + NGT: GIP (0 nM), 69.39 ± 24.65 nmol/mg of VAT vs. GIP (1 nM), 45.49 ± 20.43 nmol/mg of VAT, Δ −34.44%, p < 0.05 and Ob + Pre-T2D: GIP (0 nM), 45.33 ± 15.61 nmol/mg of VAT vs. GIP (1 nM), 29.56 ± 13.90 nmol/mg of VAT, Δ −41.41%, p < 0.05). This evidence concerns the gene GIP and type 2 diabetes mellitus.