The Glycemic Index, developed at U of T, offers a dietary plan for controlling diabetes
Diabetes is a complex condition that researchers are still trying to unravel. In basic terms, the disease impairs the way food is processed into the glucose that fuels our bodies. People with Type 2, or adult-onset, diabetes continue to produce their own insulin, the all-important hormone (secreted by the pancreas) that regulates glucose. But for some mysterious reason, in Type 2 diabetes this delicate hormonal balancing act falters, and blood glucose rises to unhealthy levels. (In Type 1, or juvenile, diabetes, the body stops producing insulin altogether.)
According to Dr. Thomas Wolever, a diabetes researcher and professor in the department of nutritional sciences, the goal of diabetes management is to bring blood-glucose levels into the healthiest possible range via proper nutrition, physical activity, regular glucose monitoring, the use of oral medications and/or insulin as required and stress reduction.
One aspect of proper nutrition involves making the best possible food choices, says Dr. Wolever. Twenty years ago, he and colleague David Jenkins, a professor of nutritional sciences and director of the Clinical Nutrition and Risk Factor Modification Centre at St. Michael’s Hospital, developed the Glycemic Index (GI) system, which ranks a wide variety of foods according to how they affect blood-glucose levels in the body. Foods low on the index (such as barley, pasta, parboiled rice, oatmeal and whole-grain pumpernickel bread) produce a gradual rise in blood sugar, which is easier on the body; foods high on the index (such as mashed potatoes, white bread, many cold breakfast cereals and crackers) cause blood-glucose and insulin levels to spike, which may be harmful. (For more information, read The Glucose Revolution: The Authoritative Guide to the Glycemic Index, or check out www.glycemicindex.com).
Several studies have found that people newly diagnosed with diabetes who learn to follow the GI system tend to make healthier food choices and have better blood-glucose and lipid (blood fat) levels than those who follow traditional dietary advice. Some research suggests that choosing foods low on the index may reduce a person’s risk of developing Type 2 diabetes in the first place.
Although the Glycemic Index system is currently recommended by the World Health Organization and other expert bodies, its use is somewhat controversial. Some doctors feel the system is too complicated for patients; others argue that the real problem for those with Type 2 diabetes isn’t the glycemic nature of what they eat, but rather that they are consuming too many calories.