Natalie asks: My friend told me about the glycaemic index diet. What is it exactly?
Wynnie says: The glycaemic index (GI) is used as the basis for a number of diets such as South Beach, The Zone and Sugar Busters. These diets are based on the theory that high-GI foods raise blood sugar levels. This causes the body to produce too much insulin, which leads to the storage of fat.
Sugar basics
Sugar, or glucose, comes from two main sources: carbohydrates found in food, and stored carbohydrates in the liver and muscles. Sugar, starch and fibre are all carbohydrates. After eating or drinking anything with carbs, the body digests sugar and starch in the same way - converting them to glucose. Fibre passes through the body essentially undigested. The glucose is then absorbed into the bloodstream where it's taken into every cell in the body to provide fuel or energy.
Blood sugar levels are regulated by two equal and opposite hormones: insulin and glucagon.
While sugar is needed for fuel, too much can be harmful. The pancreas releases insulin to remove glucose from the blood, and send the sugar to the body's fat stores. If insulin levels are raised too often, glucose remains in the bloodstream causing damage to cells, rather than being delivered to places where it's needed. This is associated with chronic diseases such as diabetes, heart disease, high blood pressure and stroke.
