Researchers from Adelaide, Australia and Durham, North Carolina were involved in this study, in which a low-carb diet, low in saturated fat but high in unsaturated fat, was compared to a high-carb, low-fat diet. The latter diet is advocated by the NHS for diabetes management. Both diets had an equal energy intake of 1,433 kcal per day.
115 obese adults with type 2 diabetes were randomised to either the high-carb or low-carb diet. Participants on the low-carb diet ate less than 50g carbohydrate per day, with fat content consisting largely of nuts, avocado and low-fat dairy. Those on the high-carb diet ate around 180g carbohydrate per day.
Over a 52-week study period, both groups experienced weight loss of around 22 lbs (10kg) and HbA1c reductions of 11 mmol/mol (1.0 per cent). Both groups also had reduced cholesterol levels: the low-carb diet reduced triglyceride levels and improved HDL (known as good cholesterol) levels, while the high-carb, low-fat diet led to greater reductions in LDL (known as bad cholesterol) levels.
However, the biggest result was that those in the low-carb diet group reduced their medication levels by 40 per cent. This was measured using the diabetes medication score.
Low-carb dieters experienced a reduction of 0.5 arbitrary units compared to a smaller reduction of 0.2 units in the high-carb, low-fat group. By reducing medication levels, type 2 diabetes is less likely to develop as quickly.
Professor Grant Brinkworth, School of Health Sciences, University of South Australia, said: “The most amazing benefit of the low carbohydrate diet was the reduction in the patient’s medication levels, which was more than double the amount than the volunteers following the lifestyle program with the high-carbohydrate diet plan.
“This research shows that traditional dietary approaches for managing type 2 diabetes could be outdated, we really need to review the current dietary guidelines if we are serious about using the latest scientific evidence to reduce the impact of the disease.”
The findings were published in the American Journal of Clinical Nutrition.