Factors That Affect the GI of a Food

A number of factors can influence the GI value of a food or meal, including:

• The type of sugar: It’s a misconception that all sugars have a high GI. The GI of sugar actually ranges from as low as 19 for fructose to up to 105 for maltose. Therefore, the GI of a food partly depends on the type of sugar it contains.
• Structure of the starch: Starch is a carbohydrate made up of two molecules, amylose and amylopectin. Amylose is difficult to digest, whereas amylopectin is easily digested. Foods with a higher amylose content will have a lower GI.
• How refined the carbohydrate is: Processing methods such as grinding and rolling disrupt amylose and amylopectin molecules, raising the GI. Generally speaking, the more processed a food is, the higher its GI.
• Nutrient composition: Both fat and acid slow down the rate at which a food is digested and absorbed, resulting in a lower GI. Adding fats or acids, such as avocado or lemon juice, will lower the GI of a meal.
• Cooking method: Preparation and cooking techniques can change the GI too. Generally, the longer a food is cooked, the faster its sugars will be digested and absorbed, raising the GI.
• Ripeness: Unripe fruit contains complex carbohydrates that break down into sugars as the fruit ripens. The riper the fruit, the higher its GI. For example, an unripe banana has a GI of 30, whereas an overripe banana has a GI of 48.

SUMMARY:The GI of a food or meal is influenced by a number of factors, including the type of sugar, structure of the starch, level of ripeness and cooking method.

Source: Link by Daisy Coyle