Utility of a short-term 25% carbohydrate diet on improving glycemic control in type 2 diabetes mellitus

To determine if introduction of a low carbohydrate diet might be a useful option for type 2 diabetic patients who do not achieve glucose target levels despite conventional treatment.

Subjects with type 2 diabetes, either treated with diet alone (n=9) or second generation sulfonylurea agents (n= 19), which were discontinued, were placed on a diet based on ideal body weight and comprised of 25% carbohydrate. After a mean of 8 weeks, they were then switched to a caloricly equivalent diet, but composed of 55% carbohydrate.

Compared to baseline diet, after 8 weeks of a 25% diet, subjects showed significantly improved glycemia as evidenced by fasting blood glucose values (p<0.005) and hemoglobin A1c levels (p<0.05). Those previously treated with oral hypoglycemic agents showed, in addition, a significant decrease in weight and diastolic blood pressure despite the discontinuation of the oral agent. When then placed on a 55% carbohydrate diet, the hemoglobin A1c rose significantly over the ensuing next 12 weeks (p<0.05).

A low carbohydrate, caloricly-restricted diet has beneficial short-term effects in subjects with type 2 who have failed either diet or sulfonylurea therapy and may obviate the necessity for insulin. Our study also affirms the need for reassessing the role of diet whenever type 2 diabetic patients manifests hyperglycemia, despite conventional oral treatment or diet management.