BACKGROUND: The Dietary Approaches to Stop Hypertension (DASH) diet is recommended for adults with diabetes. However, the effects of the DASH diet on glucose control and variability have not been thoroughly investigated. STUDY AIM: To study the effects of a modified DASH diet on glycemic control and glucose variability assessed by continuous glucose monitoring (CGM) in individuals with hypertension and type 2 diabetes. METHODS: We conducted an ancillary study to add CGM to the Dietary Approaches to Stop Hypertension for Diabetes (DASH4D) Trial. The DASH4D Trial was designed to determine the effects, alone and combined, of a modified DASH diet (vs a diet typical of what Americans with diabetes eat) and lower (vs higher) sodium intake on systolic blood pressure among people with type 2 diabetes and elevated blood pressure. Participants were fed each of the 4 study diets for 5 weeks in a random order. We invited all participants enrolling in the DASH4D Trial to wear a masked CGM sensor for up to 14 days during screening and during each of the four 5-week feeding periods. The DASH4D-CGM Study primarily aimed to evaluate the effects of the modified DASH diet (vs comparison diet) on glycemic control (mean glucose and time-in-range) and glucose variability (coefficient of variation). CONCLUSION: Combining CGM technology and a controlled feeding design, the DASH4D-CGM Study will generate robust data on the effects of diet on glycemic control and variability. These findings will inform dietary recommendations for adults with type 2 diabetes.