Adopting a DASH or WFPB diet led to significant reductions in daily insulin usage among individuals with insulin-treated type 2 diabetes. The WFPB diet led to improvements in insulin resistance and insulin sensitivity, which then regressed during the subsequent DASH 2 diet. The WFPB diet led to improvements in various cardiometabolic markers, which then worsened during the subsequent DASH 2 diet. This evidence concerns the gene INS and type 2 diabetes mellitus.