The Glycemic Index (GI) is a relative ranking of carbohydrate in foods according to how they affect blood glucose levels. Carbohydrates with a low GI value (55 or less) are more slowly digested, absorbed and metabolised and cause a lower and slower rise in blood glucose and, therefore usually, insulin levels.
There is very high level evidence from around the world that low GI diets are beneficial for health. Here's a few examples...
A recent Cochrane review found that overweight and obese people lost more weight and perhaps more importantly more fat (on average 1 kilogram or 2.2 pounds more), on low GI diets than on similar energy high GI or other conventional energy-restricted weight loss diets.
Diogenes, a randomised controlled trial in humans, found that moderately high protein, low GI diets are better for longer term weight maintenance, compared to conventional diets.
A recent Cochrane review found that low GI diets can help people with diabetes reduce their HbA1c by 0.5%. This will help decrease the risk of common diabetic complications by ~20%.
A recent systematic literature review and meta-analysis of observational studies has found that a high GL diet is associated with a 45% increase in the risk of developing type 2 diabetes.
Little wonder that people with diabetes and those at risk are advised to follow a low GI diet by all of the world’s leading diabetes organisations (e.g., American Diabetes Association; Canadian Diabetes Association and Diabetes UK).
A recent systematic literature review and meta-analysis of observational studies has found that a high GI diet is associated with a 26% increase in the risk of coronary heart disease in women.