A low-carbohydrate diet is more effective in reducing body weight than healthy eating in both diabetic and non-diabetic subjects

Background Low-carbohydrate diets are effective for weight reduction in people without diabetes, but there is limited evidence for people with Type 2 diabetes. Aims To assess the impact of a low-carbohydrate diet on body weight, glycated haemoglobin (HbA1c), ketone and lipid levels in diabetic and non-diabetic subjects. Methods Thirteen Type 2 diabetic subjects (on diet or metformin) and 13 non-diabetic subjects were randomly allocated to either a low-carbohydrate diet (≤ 40 g carbohydrate/day) or a healthy-eating diet following Diabetes UK nutritional recommendations and were seen monthly for 3 months. Subjects (25% male) were (mean ± sd) age 52 ± 9 years, weight 96.3 ± 16.6 kg, body mass index 35.1 kg/m2, HbA1c 6.6 ± 1.1%, total cholesterol 5.1 ± 1.1 mmol/l, high-density lipoprotein cholesterol 1.3 ± 0.4 mmol/l, low-density lipoprotein cholesterol 3.1 ± 0.9 mmol/l, triglycerides (geometric mean) 1.55 (1.10, 2.35) mmol/l and ketones range 0.0–0.2 mmol/l. Results Analysis was by intention to treat with last observation carried forward. Twenty-two of the participants (85%) completed the study. Weight loss was greater (6.9 vs. 2.1 kg, P = 0.003) in the low-carbohydrate group, with no difference in changes in HbA1c, ketone or lipid levels. Conclusions The diet was equally effective in those with and without diabetes.