Low carbohydrate diet may help lower blood sugar and hepatic fat in diabetics

Copenhagen, Denmark: A carbohydrate-reduced high-protein (CRHP) diet may help to lower blood sugar levels in patients with type 2 diabetes even in the absence of recommended weight loss or a low-carb/low-fat diet, finds a recent study. The study can be reassuring to the patients who feel the need to completely cut carbohydrate intake to see an improvement in their diabetes.

According to the study, published in the journal Diabetologia, a moderate shift in macronutrient by substituting carbohydrates with fat and protein for 6 weeks reduced, hepatic fat and HbA_1c, in weight stable people with type 2 diabetes.

Nutritional therapy is important to treat type 2 diabetes optimally, but the recommendations are unclear but there is an increasing trend towards a diet with reduced carbohydrate content. According to the Danish Health Authority, up to 85% of newly diagnosed patients with type 2 diabetes are overweight, and they are typically advised to follow a diet focused on weight loss: containing fewer calories than they burn, low-fat content and a high content of carbohydrates with a low ‘glycaemic index’ (which indicates how quickly a food affects blood sugar levels.

Mads J. Skytte, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark, and colleagues compared a CRHP diet with iso-energetic conventional diabetes (CD) diet to elucidate the effects on glycaemic control and selected cardiovascular risk markers during 6 weeks of full food provision of each diet.

The study included men and women with type 2 diabetes, HbA1c 48-97 mmol/mol (6.5-11%), age >18 years, haemoglobin >6/>7 mmol/l (women/men) and eGFR >30 ml min-1 (1.73 m)-2. Participants were randomized by drawing blinded ballots to 6 + 6 weeks of an iso-energetic CRHP vs CD diet in an open-label, crossover design aiming at bodyweight stability. he CRHP/CD diets contained carbohydrate 30/50 energy percent (E%), protein 30/17E% and fat 40/33E%, respectively. Participants underwent a meal test at the end of each diet period and glycaemic variables, lipid profiles, 24 h blood pressure and ectopic fat including liver and pancreatic fat content were assessed at baseline and at the end of each diet period.

The primary outcome of the study was a change in HbA1c. Secondary outcomes reported in the present paper include glycaemic variables, ectopic fat content and 24 h blood pressure.

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Key findings of the study include:

• Twenty-eight participants completed the study.


• Fourteen participants carried out 6 weeks of the CRHP intervention followed by 6 weeks of the CD intervention, and 14 participants received the dietary interventions in the reverse order.


• Compared with a CD diet, a CRHP diet reduced the primary outcome of HbA1c (mean ± SEM: -6.2 ± 0.8 mmol/mol vs -0.75 ± 1.0 mmol/mol).


• Nine (out of 37) pre-specified secondary outcomes are reported in the present paper, of which five were significantly different between the diets; compared with a CD diet, a CRHP diet reduced the secondary outcomes (mean ± SEM or medians [interquartile range]) of fasting plasma glucose (-0.71 ± 0.20 mmol/l vs 0.03 ± 0.23 mmol/l), postprandial plasma glucose AUC (9.58 ± 0.29 mmol/l × 240 min vs 11.89 ± 0.43 mmol/l × 240 min) and net AUC (1.25 ± 0.20 mmol/l × 240 min vs 3.10 ± 0.25 mmol/l × 240 min), hepatic fat content (-2.4% vs 0.2%) and pancreatic fat content (-1.7% vs 0.5%).


• Changes in other secondary outcomes, i.e. 24 h blood pressure and muscle-, visceral- or subcutaneous adipose tissue, did not differ between diets.

"Carbohydrate restriction may be an effective tool for improving glycemic control as well as reducing hepatic fat content in individuals with type 2 diabetes, even in the absence of weight loss," concluded the authors.

The study, "A carbohydrate-reduced high-protein diet improves HbA_1c and liver fat content in weight stable participants with type 2 diabetes: a randomised controlled trial," is published in the Diabetologia journal.