More Evidence: Low-carb Diet Can Improve Diabetes Control and Reduce Meds

In fact, the diet allows some patients to reduce or eliminate their medication, according to the report in the medical journal Nutrition and Metabolism.

Carbohydrate restriction is at the heart of a diabetic diet. A very low carb diet causes the body to use protein to provide energy, which produces ketones, and it is therefore called a ketogenic diet. Another dietary approach is to use foods with a low glycemic index, ie, that don't cause a rapid rise in blood sugar, and to cut back on calories.

Dr. Eric C. Westman, of Duke University Medical Center, Durham, North Carolina, and colleagues compared the effectiveness of the two diets in 84 obese patients with type 2 diabetes. They were assigned to a low carbohydrate (less than 20 grams per day) ketogenic diet or to low-glycemic reduced-calorie diet for 24-weeks. Those on the low-carb ketogenic diet had no restrictions on their daily calorie intake.

Patients in the low-carbohydrate, ketogenic diet had greater improvements in hemoglobin A1c than those in the low-glycemic, reduced-calorie diet group (-1.5% versus 0.5%, p = 0.03).

Those in the low-carb ketogenic diet group also lost more weight and had an increase in "good" HDL cholesterol compared with those in the other diet group.

Those in the low-carb, ketogenic diet group also had greater reductions in body weight (-11.1 kg versus -6.9 kg, p = 0.008), and high density lipoprotein cholesterol (+5.6 mg/dL versus 0 mg/dL, p < 0.001) compared with those in the low-glycemic, reduced-calorie diet group.

"In terms of renal function, serum creatinine and calculated glomerular filtration rate did not change significantly over the 24 weeks for either group," Dr. Westman and colleagues report. "There was a greater reduction in 24-hour urine protein for the low-carbohydrate, ketogenic diet group compared with the low-glycemic, reduced-calorie diet group."

An elimination or reduction in diabetes medication was possible for 95.2% of low-carbohydrate, ketogenic diet patients and 62.1% of low-glycemic, reduced-calorie diet patients (p < 0.01).

"Lifestyle modification using low carbohydrate interventions is effective for improving and reversing type 2 diabetes," the researchers conclude.

Nutrition and Metabolism, December 2008.