Low-carbohydrate dietary approaches can lead to improvements in blood glucose levels and weight loss, as well as a reduction and/or cessation in medication use in people with type 2 diabetes (T2D). Recent technological advances have led to the development of health-related applications (apps), including a high proportion dedicated to the management of diabetes. The Defeat Diabetes Program is a smartphone- and web-based app that provides guidance on a low-carbohydrate dietary approach for T2D and was designed to be used in conjunction with standard care in the medical management of T2D. The primary aim of this protocol is to provide the rationale and design of a single-arm 12-month pre–post intervention clinical trial using the Defeat Diabetes Program in an Australian community-based cohort of people with T2D who were referred by their general practitioner (GP). The study seeks to engage the GP community to help demonstrate whether the results of using a low-carbohydrate dietary approach for T2D can be achieved by the Defeat Diabetes Program in their patients. This protocol describes (1) the rationale for the selection of primary and secondary outcome measures, (2) the sampling procedures and methodological steps used to identify eligible participants and collect data, and (3) the approach followed to involve and educate GPs to support the trial.