The glycemic index: where are we now and where are we going?

From controversial beginnings in the 1980s, the glycemic index (GI) has stood the test of time and scientific scrutiny. It is now considered a fundamental concept in nutrition science and is the subject of hundreds of scientific papers each year, some of them in the highest impact medical journals (Pawlak & others 2004). Officially, the GI is recommended by major diabetes associations, including Diabetes UK (2003), Canadian Diabetes Association (2000) and Diabetes Australia (Barclay 1998). Most recently, the American Diabetes Association officially recognised that the GI 'can provide an additional benefit over that observed when total carbohydrate is considered alone' (Sheard & others 2004). The application of the GI in other areas, eg weight control (Ebbeling & others 2003), sports performance (Burke & others 1993), cardiovascular disease (Brynes & others 2003), cancer prevention (Francheschi 1996, Francheschi & others 1997), is the subject of ongoing research. While the evidence base is still limited, the GI is being applied to the management of all the diseases linked to insulin resistance, including the metabolic syndrome, polycystic ovary syndrome (PCOS) (Marsh & Brand-Miller 2005), non-alcoholic fatty liver disease (NAFLD), and in novel areas such as cognitive performance, memory and learning (Benton & others 2003).