In patients with diabetes mellitus, the toxic milieu caused by abnormal glucose and free fatty acid handling can lead to heart failure (HF). Referred to as diabetic cardiomyopathy (DMCM), this syndrome often exists in the absence of conventional risk factors for HF such as history of myocardial infarction or hypertension. Low-carbohydrate diets (LCDs) have recently been endorsed as an efficacious therapeutic dietary approach to prevent and reverse cardiometabolic disease including type 2 diabetes mellitus (T2DM). LCDs improve systemic insulin resistance (IR), reverses cardiac remodelling in a rodent model and downregulates the expression of sodium–glucose co-transporter 2 (SGLT2) receptors in the kidney. It is therefore conceivable that a lifestyle approach such as adopting an LCD can be offered to patients with DMCM. The reported case is that of a 45-year-old man with a 15-year history of non-ischaemic cardiomyopathy, T2DM and obesity. The patient volunteered to engage in a 16-week low-carbohydrate dietary intervention trial and then self-selected to remain on this diet for 1 year. The whole-food LCD was based on simple ‘traffic light’ style food lists and not designed to restrict calories, protein, fat or salt. After 1 year, the patient had lost 39 kg and his cardiometabolic markers had significantly improved. LCDs present a potentially beneficial approach for patients with DMCM and could be considered as a lifestyle intervention before SGLT2i therapy is commenced.