The rate of type 2 diabetes has risen exponentially among adolescents, Dr. Steven M. Willi and colleagues from the Medical University of South Carolina, Charleston, point out in the medical journal Diabetes Care, but there are few studies comparing the relative merits of diet, exercise, insulin, and other drug therapies in treating such patients.

The team evaluated the ability of a ketogenic, very-low-calorie diet to reduce weight, reduce high blood sugar levels, and decrease the dependence on anti-diabetes medications in 20 obese teens -- 5 males and 15 females -- with type 2 diabetes.

The diet consisted of about 100 grams of protein and less than 30 grams each of fat and carbohydrates per day, which delivered between 680 and 800 calories. That translates to approximately 13 ounces of lean meat and 3 cups of vegetables. The participants also needed to take in 8 cups of fluid and supplemental salt daily.

Mean daily blood glucose levels fell from 162 to 100 mg/dL within three days of beginning the diet, and all but one teen managed to discontinue all antidiabetic therapy.

After voluntarily stopping the diet after an average of 60 days, participants' average weight loss was 25 pounds (9.3 percent of total body weight), the researchers report.

In fact, the average body weight was still significantly reduced two years later. This amounted to a 5.4 percent reduction, compared with a 3.7 percent increase in an age-matched control group.

Average blood pressure also fell during the diet, and none of the patients experienced side effects such as nausea and cramps reported in previous trials of the diet in youngsters, Willi's team found.

The investigators call for further studies, but conclude that "the very-low-calorie diet has the potential to improve diabetes control over the short term and perhaps empower diabetic individuals over the long term."