The Glycemic Index (GI) of a food reflects the rate and extent to which a food raises blood sugar levels compared to glucose.
How is GI calculated?
The GI is determined by comparing the blood sugar response of 50 grams of a specific carbohydrate-containing food to 50 grams of pure glucose. The area under the blood sugar response curve for the food is divided by the area under the blood sugar response curve for glucose and then multiplied by 100. Glucose has a GI of 100.
Foods with a GI greater than 70 are considered high GI foods. These foods are digested quickly in the gastrointestinal tract, have a high absorption rate, and convert to glucose rapidly, causing a swift increase in blood sugar levels.
Foods with a GI of 55 or less are considered low GI foods. These foods stay in the gastrointestinal tract longer, have a lower absorption rate, and convert to glucose more slowly, resulting in a gradual rise in blood sugar levels. This allows the body ample time to release and synthesize insulin, preventing a sharp spike in blood sugar levels.
In daily life, it's important to avoid overconsumption of any type of food. Even low GI foods, if eaten in excess, can burden postprandial blood sugar levels. High GI foods are not completely off-limits; consuming them in moderation and with balanced combinations can help maintain blood sugar homeostasis.