the lack of standardized definitions for terms such as "lowfat (or high-fat) diet," "low-carbohydrate (or high-carbohydrate) diet," and "lowGI (or high-GI) diet" makes comparisons among study results difficult. [...] due to the large volume and variety of research regarding diet and diabetes-related health outcomes, rigorous systematic reviews and meta-analyses need to be conducted so that researchers, clinicians, patients, and funding agencies are aware of the most recent research and the direction in which it is heading.