Aims/hypothesis Dietary recommendations for treating type 2 diabetes are unclear but a trend towards recommending a diet reduced in carbohydrate content is acknowledged. We compared a carbohydrate-reduced high-protein (CRHP) diet with an isoenergetic conventional diabetes (CD) diet to elucidate the effects on glycaemic control and selected cardiovascular risk markers during 6 weeks of full food provision of each diet. Methods The primary outcome of the study was change in HbA 1c. Secondary outcomes reported in the present paper include glycaemic variables, ectopic fat content and 24 h blood pressure. Eligibility criteria were: men and women with type 2 diabetes, HbA 1c 48-97 mmol/mol (6.5-11%), age >18 years, haemoglobin >6/>7 mmol/l (women/men) and eGFR >30 ml min −1 (1.73 m) −2. Participants were randomised by drawing blinded ballots to 6 + 6 weeks of an iso-energetic CRHP vs CD diet in an open label, crossover design aiming at body weight stability. The CRHP/CD diets contained carbohydrate 30/50 energy per cent (E%), protein 30/17E% and fat 40/33E%, respectively. Participants underwent a meal test at the end of each diet period and glycaemic variables, lipid profiles, 24 h blood pressure and ectopic fat including liver and pancreatic fat content were assessed at baseline and at the end of each diet period.