A Glycemic Index (GI) diet is a description used for any weight-loss diet that focuses on blood sugar levels. A GI diet uses the glycemic index as a guide, which classifies foods containing carbohydrates according to their potential to raise blood sugar levels.

A GI diet isn’t a true low carb diet, nor is it a low fat diet as you don't have to count calories or cut out carbs completely. However a GI diet does steer you toward certain types of food with low GI rankings.

The GI ranks foods based on how they affect blood sugar levels. Foods are measured on an index of 0 to 100. Only foods that are high in carbs are ranked, as they cause the largest changes to blood sugar. There are extensive lists online of GI rankings, but many foods remain unranked.

Sugar (glucose) is a source of energy for the cells that constitute your body. The largest source of glucose is carbohydrates in food. There is also a reserve of glucose in your liver. Carbohydrates are found in sugar, starch and fiber. After you eat food containing carbs, you break down the carbs through the process of catabolism, releasing glucose into your bloodstream.

Two hormones from your pancreas help regulate your level of blood sugar. Insulin moves glucose to your cells from your blood when your blood sugar level is high. Excess glucose is stored in your liver in a form called glycogen. The hormone glucagon helps release the glycogen from your liver when your blood sugar level is low. These processes help keep your body fuelled and ensure a normal balance in blood sugar.

Foods with a high GI ranking are quickly digested, and may disrupt this natural balance by creating large peaks in your blood sugar level. if your blood sugar and insulin levels remain high, or cycle high and low quickly, your body has trouble responding. Over time this could lead to insulin resistance. Insulin resistance is associated with a host of health problems, including stroke, type 2 diabetes and heart disease.

Foods with lower GI rankings are digested more slowly, avoiding large spikes and allowing blood sugar levels to be more easily regulated. Low GI foods stay in your digestive system longer. This may delay hunger cues and help control appetite. This can help with weight loss.

Whilst a low GI diet is generally a good idea, there is no need to seek out purely low GI foods. Avoid the trap of thinking low GI foods are always healthy. Ice cream and potato chips have low GI scores, but are no good for those trying to lose weight.

There are two simple ways to have a low GI diet. Combine higher GI foods with lean proteins and vegetables which have low GI scores. This will lower the overall GI rating of your meal. Also, eat smaller meals, more regularly. Both methods will help maintain blood sugar at a steady level and help with weight management.