A glycemic index diet is based on the theory that keeping blood sugar, or blood glucose, levels in a steady range can lead to weight loss. The diet is designed around low-glycemic foods that help prevent rapid increases in blood glucose levels. According to MayoClinic.com, the glycemic index diet was originally developed to control blood sugar levels in diabetics.
Physiology of Blood
Glucose is the main source of energy for the body. The liver is able to store some glucose, but most of it comes from carbohydrates in the diet. When carbohydrates are consumed, the body breaks them down into sugar molecules, which then enter the bloodstream. When sugar enters the bloodstream, the pancreas releases two hormones, insulin and glucagon, to regulate it. Insulin helps transfer sugar from the blood into the body cells and glucagon releases stored glucose from the liver when blood sugar gets too low.
Blood Sugar and Weight
Carbohydrates that are considered high in the glycemic index can cause rapid increases in blood sugar levels. When blood sugar levels increase too quickly, it can be difficult for the body to regulate them correctly. This can cause blood sugar levels, as well as insulin levels, to remain high over time. Consistently high blood sugar and insulin levels lead to a condition called insulin resistance, which means the body does not respond well to insulin. MayoClinic.com notes that insulin resistance can lead to weight gain. Keeping blood sugar levels steady prevents the pancreas from releasing too much insulin, which can help the body lose weight.
Glycemic Index Categories
There are three categories in a glycemic index diet: high, medium and low. Foods that are given a glycemic index ranking of 70 or more are considered high. Medium foods are those with a glycemic index between 56 and 69. A low glycemic index ranking is 55 and less. The goal for a glycemic index diet is to consume mostly low glycemic index foods and occasional medium glycemic index foods. Those on a glycemic index diet should avoid high glycemic foods as much as possible.
Foods to Eat
Foods with the lowest glycemic indexes include whole-grains, nuts, legumes and non-starchy vegetables, such as broccoli, spinach and kale. Fruits that have a low glycemic index include oranges, pears and apples, according to the Linus Pauling Institute.
Foods to Avoid
Foods with high glycemic indexes include white breads, white rice, potatoes and other starchy vegetables, such as corn and green peas. When following a glycemic index diet, these foods should be avoided. Sugary drinks, such as soda and fruit juice, should also be avoided on this diet.
