The Diabetes Prevention Program (DPP) demonstrated that lifestyle intervention programs were effective in preventing or delaying the onset of diabetes. The Group Lifestyle Balance (GLB) program translated the DPP curriculum into a 12-wk group intervention for those at risk for diabetes. This retrospective evaluation examined clinical outcomes for patients in the Diabetes Center of Excellence GLB program located at Wilford Hall Ambulatory Surgical Center from 2009 to 2013. Objectives included determining rates of retention, demographic characteristics of program completers, and changes in metabolic surrogates of disease prevalence.Adults with prediabetes or metabolic syndrome (MetS) were referred to the GLB program. Updated participant metabolic data were collected at regular intervals during their participation.During the 5-yr study, 704 patients attended the initial class. Overall, 52% of all participants completed the program with the greatest decline in participation occurring by the fourth week (30%). Baseline prevalence of conditions of interest for those who completed the program was prediabetes (93.2%), obesity (56.1%), and MetS (31.5%). GLB completers were older and retired (p < 0.05). A significant number of active duty military members (44.9%, p < 0.01, n = 53) dropped out of the program before the fourth week. Furthermore, those who completed the program saw a 2.0% reduction in prediabetes prevalence (p < 0.001), obesity decreased by 8.7% (p < 0.001), and MetS decreased by 6.8% (p < 0.01). Significant differences were found for central obesity, triglycerides, and fasting blood sugar (p < 0.001).The GLB program is a valuable DPP and was effective at improving clinical outcomes and reducing the incidence of prediabetes, obesity, and MetS for participants who completed the program. Every effort should be made to support and encourage GLB participants to complete the program.