Objective Modest weight loss from clinical interventions improves glycemic control in type 2 diabetes (T2DM). Data are sparse on the effects of weight loss via commercial weight loss programs. This study examined the effects on glycemic control and weight loss of the standard Weight Watchers program, combined with telephone and email consultations with a certified diabetes educator (WW), compared with standard diabetes nutrition counseling and education (standard care, SC). Methods In a 12-month randomized controlled trial at 16 U.S. research centers, 563 adults with T2DM (HbA1c 7–11%; BMI 27–50 kg/m2) were assigned to either the commercially available WW program (regular community meetings, online tools), plus telephone and email counseling from a certified diabetes educator, or to SC (initial in-person diabetes nutrition counseling/education, with follow-up informational materials). Results Follow-up rate was 86%. Twelve-month HbA1c changes for WW and SC were −0.32 and +0.16, respectively; 24% of WW versus 14% of SC achieved HbA1c
