Diabetic Educational Eating Plan (DEEP)

The glycemic index (GI) is a ranking of carbohydrate containing foods according to the rate at which they raise blood glucose levels after eating. A recent meta-analysis of randomized clinical trials (RCT) suggests that choosing low GI foods has a small but clinically useful effect on medium-term glycemic control in patients with type 2 diabetes. However, in most of the reviewed RCTs, patients were fed experimental diets and therefore there is still controversy over the applicability of GI in the clinical setting for management of diabetes. In addition, there is no evidence that long-term consumption of a low GI diet will contribute to improved glycemic control in people with diabetes.

Our ultimate goal for a future larger RCT is to evaluate the long-term effects of using low GI diet in type 2 diabetics. The primary outcome variable of the future large trial will be glycosylated hemoglobin levels (HbA1c), a measure reflecting average glycemic level during the preceding 2-3 months. The proposed feasibility study will recruit 40 patients with type 2 diabetes and will randomly assign them to one of two groups: a low GI nutrition education group (low GI group) and a standard ADA dietary education group as the control group (ADA group) (20 patients in each group).

For both groups, the intervention phase will last 6 months and consist of an initial group session, an individual session, and then four group counseling sessions. The follow-up phase will be six months and consist of two group booster sessions, one at 8-months and another at 10-months. The low GI nutritional education will be primarily targeted at a low GI diet. The focus is not on decreasing total carbohydrate intake, but rather encouraging patients to substitute low GI foods for high GI foods. The dietary intervention will be based on a patient-centered counseling model which has been demonstrated to facilitate health behavior change. Data collection points coincide with two phases of the intervention. Assessments, including demographics, anthropometric measurements, diet and physical activity recalls, and clinical data, will be conducted at baseline, and at 6 and 12 months after randomization, with blood samples collected at each interval. We will track response to recruitment, adherence, and retention. Quantitative and qualitative methods will be used to assess acceptability of the intervention.

The aim of this proposed 2-year study is to gather pilot data on the feasibility of implementing a nutritionist-delivered low GI intervention to reduce dietary GI in patients with type 2 diabetes. Our outcomes are recruitment and retention rates, as well as physiological measures (HbA1c, blood pressure, and body mass index), dietary GI scores and acceptability of the intervention.

By improving glycemic control, many of the devastating complications of diabetes are to a large extent preventable. The use of a low GI diet to improve glycemic control is relatively new and untested. However, a low GI diet may be a cost-effective approach to preventing diabetes-related complications. Testing the feasibility of such a program and its potential impact would be an important step towards an RO1 application to the NIH.