The study included a comprehensive PubMed search of human studies published from 1965 to December 2010. All study data involved patients with various comorbidities that studied the benefits of whole grain, fiber and whole bran diets as they related to improvements in each patent's disease state.
Results from the study review showed that most whole-grain studies included mixtures of whole grains and foods with ≥25% bran. Prospective studies consistently showed a reduced risk of type 2 diabetes with high intakes of cereal fiber or mixtures of whole grains and bran. For body weight, a limited number of prospective studies on cereal fiber and whole grains reported small but significant reductions in weight gain. For cardiovascular disease, studies found reduced risk with high intakes of cereal fiber or mixtures of whole grains and bran.
In conclusion, the researchers suggested that the ASN position, based on the current state of the science, is that consumption of foods rich in cereal fiber or mixtures of whole grains and bran is modestly associated with a reduced risk of obesity, type 2 diabetes, and cardiovascular disease. Researchers also noted that consuming fiber may allow a diabetic patient to eat relatively more carbohydrates without running the risk of hyperglycemia.
Cho, Susan S. "Consumption of cereal fiber, mixtures of whole grains and bran, and whole grains and risk reduction in type 2 diabetes, obesity, and cardiovascular disease." American Society for Nutrition. (2013): n. page. Web. 14 Jul. 2013.