Skip to main content

What is the Glycemic Index

  • Synopsis: Published: 2011-01-10 (Revised/Updated 2017-02-07) - The glycemic index is a measure of the effects of carbohydrates on blood sugar levels. For further information pertaining to this article contact: Health Choices at healthchoices.ca.
Glycemic Index

The glycemic index or glycaemic index (GI) is a number associated with a particular type of food that indicates the food's effect on a person's blood glucose (blood sugar) level. A value of 100 represents the standard, an equivalent amount of pure glucose. The glycemic index is usually applied in the context of the quantity of the food and the amount of carbohydrate in the food that is actually consumed. The glycemic response is different from one person to another, and also in the same person from day to day, depending on blood glucose levels, insulin resistance, and other factors.

Main Document

Quote: "Many people use the glycemic index to help them select foods for meal planning, but it can be hard to follow a glycemic index diet on your own to manage your diabetes."

The glycemic index is a measure of the effects of carbohydrates on blood sugar levels. It's a ranking of foods based on their immediate effect on blood glucose (blood sugar) levels.

"The glycemic index was a concept that was introduced by Dr. David Jenkins out of the University of Toronto," says Sarah Ware, a Registered Dietitian, Certified Diabetes Educator and HealthChoices.ca partner. "It's a concept that categorizes food on how quickly it causes a rise in blood sugar once ingested; it categorizes food whether they are high glycemic or low glycemic."

Sound complicated?

It's not - the glycemic index is just a way to understand how a food will affect blood sugar. Some starchy foods have a high glycemic index, which can cause high blood sugar levels after meals.

High glycemic foods include baked potatoes and instant rice. Other foods are non-starchy, such as many vegetables, fruits and legumes, and can help prevent high blood sugar after meals.

"It's interesting to note that food like white bread or potatoes actually cause a faster blood sugar rise than a food like regular table sugar," says Ware. "So when you're choosing your meals, for example if you wanted rice for dinner try to choose wild rice over white, and when it comes to fruit choose blueberries over watermelon."

The Glycemic Index and Diabetes

The glycemic index (GI) can help diabetic patients manage blood glucose.

A recent study done by Bajorek S.A. and Morello C.M. at Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California in San Diego reports that people who took psyllium fiber supplements and followed a low glycemic index diet improved glycemic risk factors.

Many people use the glycemic index to help them select foods for meal planning, but it can be hard to follow a glycemic index diet on your own to manage your diabetes.

"If somebody has more questions about the glycemic index they should speak with a dietitian, Certified Diabetes Educator or a diabetes specialist," says Ware.

Related Information:

  1. Make the Glycemic Index Work for You
  2. High Glycemic Index Foods May Pose Greater Risk for Heart Disease in Women
  3. Blood Sugar Level Chart and Information - Information and printable chart showing diabetic blood sugar levels for persons with diabetes or pre-diabetes - Thomas C. Weiss


Information from our Diabetes: Types, Symptoms and Treatments section - (Full List).

E-Newsletter

Loan Information for low income singles, families, seniors and disabled. Includes home, vehicle and personal loans.


Famous People with Disabilities - Well known people with disabilities and conditions who contributed to society.


List of awareness ribbon colors and their meaning. Also see our calendar of awareness dates.


Blood Pressure Chart - What should your blood pressure be. Also see information on blood group types and compatibility.


  1. Mobile Phone App to Control Diabetes May be Possible Someday
  2. New Details on Aged Brain, Alzheimer's and Dementia Revealed
  3. FDA Issues Guidance on Generic Abuse-Deterrent Opioid Development
  4. Getting a Job with a Disability - Infographic with Transcript




Citation