With the recent low-carbohydrate craze, dieters avoid foods such as pasta and potatoes to limit fluctuations in their blood sugar.
The glycemic index ranks carbohydrates by how much a person's blood sugar rises immediately after eating.
Smith usually uses the index when teaching diabetic patients how to adjust their diets, but recently, people on low-carb diets have been using the table for weight-loss purposes.
Other health professionals think the concept of the index is too complicated to explain and put into practice.
Proponents of basing a diet on the glycemic index, however, maintain that eating foods lower on the list could provide many health benefits, including weight loss.
The glycemic index compares foods' carbohydrate content, gram for gram, says Dr. Thomas Wolever, a professor in the department of nutritional sciences at the University of Toronto.
At the time, glucose was used as the standard to which other foods were compared.
Since then, tests have been done using white bread as the reference, but Dr. Wolever still prefers to use glucose.
After digestion, they release glucose into the blood stream at a gradual rate, which causes a smaller rise in the blood sugar.
Therefore, eating according to the glycemic index would improve a person's control of diabetes, he says.
Eating foods low on the glycemic index doesn't mean a person would never eat a food that is higher on the table, such as white bread, Dr. Wolever says.
If a person wants to eat a food such as rice, Dr. Wolever suggests choosing a type of rice lower on the list -- parboiled rice, for example.
The glycemic index is a good tool for people who are putting a fair amount of time into considering what they eat, she says.