Glycemic Response of Bean-and-rice Meals in Type 2 Diabetes Mellitus

Overview

The study uses a randomized, placebo-controlled experimental design consisting of 4 different test treatments matched on carbohydrate (CHO) content. The three beans are similar in their CHO content amount for ½ cup at \~20 grams CHO. Each of the bean varieties will be served in a \~½ cup serving size with \~ ½ cup of plain steamed white rice (30 grams CHO) for a total of 50 grams of CHO per meal for each of the three test treatments. The 4th placebo or control treatment consists of \~ 7/8 cup of rice alone, an amount consistent with the CHO content of the test meals. Most diabetic meal plans recommend no more than 45-60 grams of CHO per meal. Fifty grams of CHO is a standard amount for glycemic response testing in general. The investigators hypotheses were: * The test meals containing the three bean types in combination with white rice will decrease the participants' glycemic response when eaten as part of a meal. * The reduction in post-prandial glycemia will not differ between bean types in the elicited responses among individuals with type 2 diabetes.

The 4 test treatments will be administered randomly on a different morning, at least one week apart. Participants will be required to consume the entire test treatment meal in 7 minutes while being observed. All test foods will be purchased from local markets. Capillary blood samples will be collected (\~50µl) at time 0 (fasting) and at 30, 60, 90, 120 and 180 minutes post-treatment (timing of the post-treatment blood draws started at time 0 \[post-treatment\], which is when the participant finishes consuming the treatment meal). Venous blood draws for insulin assessment will also be acquired at fasting and then every hour for the three hour study period. Anthropometric measures such as weight, height and waist circumference will be collected at screening and at the start of each test day. Thirteen hours before testing, participants will eat a control meal to reduce variation in glycemic responses on test days due to varying dietary intakes. This control meal will be selected by each participant before the start of the study. They will be provided a gift card to the chain restaurant to use to purchase their own meal. Since subjects serve as their own controls, the meals must be identical before each test draw. Participants will complete 24 hour recall food records the morning of each test day to provide information related to dietary protocol compliance.