In type 2 diabetes (T2D) patients, a non-calorie–restricted low-carbohydrate diet (LCD) high in fat conferred significant beneficial effects on glycaemic control and body composition, without resulting in adverse impacts on cardiovascular risk factors. Decreasing carbohydrate consumption to 10-25 E% (percentage of total energy intake) seems to be an effective as well as safe nutritional approach with respect to classical cardiovascular risk factors and hypoglycemia.

• This open-label randomized controlled trial involved randomization of T2D patients to either a LCD with a maximum of 20 E% from carbohydrates (n = 49) or a control diet with 50-60 E% from carbohydrates (n = 22) for 6 months.

• In the LCD group, carbohydrate intake was reduced to 13.4 E% and fat intake was increased to 63.2 E%, which was −30.5 ± 2.2 E% lower for carbohydrates and 30.6 ± 2.2 E% higher for fat, respectively, vs the control group.

• LCD resulted in decreased HbA1c post-3 months (−8.9 ± 1.7 mmol/mol), and this was maintained after 6 months (−7.5 ± 1.8 mmol/mol), vs the control diet.

• Reductions in weight (−3.9 ± 1.0 kg), body mass index (−1.4 ± 0.4 kg/m ² ), and waist circumference (−4.9 ± 1.3 cm) were achieved with LCD vs the control diet, which were accompanied by decreases in total fat mass (−2.2 ± 1.0 kg) and lean mass (−1.3 ± 0.6 kg).

• Following 6 months, there were no changes in blood lipids or blood pressure.

• The level of physical activity was maintained, and severe hypoglycaemia did not occur.