Keto diet may aid weight loss and glycaemic control, review says

University of Sydney researchers said ketogenic diets may help lower weight and improve glycaemic control, but long-term safety and sustainability remain unsettled in diabetes care. Their narrative review, published in Nutrients on June 20, 2026, pulled together preclinical and clinical evidence on the diet’s role in obesity and diabetes.

The paper was written by Yousun An, Nicholas Norris, Donglai Li and Jenny E. Gunton, with affiliations to the University of Sydney and the Westmead Institute for Medical Research in Sydney and Westmead, New South Wales, Australia. In the abstract, the authors described keto as a low-carbohydrate, high-fat pattern that shifts the body away from glucose use and toward fatty acid oxidation and ketone production, a change they linked to reduced hunger and the anorexigenic effects of ketone bodies. They also said lower insulin demand may help beta-cell function and improve insulin sensitivity in some patients.

That potential is why keto still draws interest from people managing obesity and type 2 diabetes. Earlier reviews found HbA1c improvements can show up within three weeks and may persist for at least a year in some studies, and a 2022 meta-analysis reported lower fasting plasma glucose, HbA1c, body mass index, weight and waist circumference in overweight or obese patients with type 2 diabetes. The same analysis found triglycerides fell and HDL tended to rise.

The caution flags are just as clear. A 2023 scoping review in adults with overweight or obesity and type 2 diabetes, covering 11 studies, found adherence was difficult to maintain and many participants ate more carbohydrate and less fat than prescribed. That is one reason the American Diabetes Association’s Standards of Care in Diabetes-2026, released on December 8, 2025, stresses individualized meal patterns, long-term sustainability and the fact that no single eating plan fits everyone. The ADA also lists low-carbohydrate eating patterns among evidence-based options for preventing type 2 diabetes.

Safety concerns sharpen when keto is paired with glucose-lowering drugs. A 2022 review of case reports identified 14 patients on SGLT2 inhibitors who developed euglycaemic diabetic ketoacidosis after starting ketogenic or very low-carbohydrate diets, and more than 90% were hospitalized within four weeks. The June 2026 review said that combination needs careful clinical supervision.

The main pattern is familiar to the keto community: the short-term numbers can look encouraging, but the long-term questions have not gone away. For readers weighing the diet for obesity or diabetes, the evidence still points to a tool that can work for some people, not a universal answer.