Knowing how much a particular food will contribute towards your blood sugar level and how soon it will do so, is important especially for diabetics. This information is garnered from the Glycemic Index (GI) of the food to be consumed.
The glycemic index or GI is a measure of the effect of carbohydrates on our blood sugar level. It is an estimation of how much our blood glucose level will increase on consumption of each gram of ‘net carbohydrate’ (carbohydrate minus fiber) in the food we are going to eat.
Glycemic Index explained
Foods with carbohydrates (carbs) are of two types; those that break down and release energy quickly (e.g. potatoes, white rice, corn flakes), and those that take some time to break down and therefore release energy more slowly (fruits, vegetables, nuts, legumes, beans, peas, etc). Medical science classifies the former group as foods with high Glycemic index (typically 70 and above) and the latter group as foods with low Glycemic index (typically 55 or less).
The reason that carbohydrate content in food is an important factor in determining GI is that the GI can only be applied to foods that have substantial carbohydrate (typically 50 grams or more) content. Most fruits and vegetables (excluding grapes and potatoes) contain very little carbohydrate per serving.
Knowing how much a particular food is going to contribute to the blood sugar level or glucose level and quickly is of immense value to a diabetic especially those suffering from diabetes type I because he or she can then accurately calculate the insulin dosage.
If you love a particular food that has moderate to high GI, then consuming a glass of wine (or stronger alcohol but not beer), before the meal will help lower the GI of the food by roughly 15%. Although not considered healthy by any stretch of imagination, you may be surprised to know that chocolate cakes and ice creams have low glycemic indices (38 and 37 respectively).
Glycemic Index and health
Apart from the correlation between foods with carbohydrates and our blood glucose levels, there is no conclusive evidence that foods with higher GI are in anyway harmful to us. For example, the peoplePeruandAsiahave a diet that consists mostly of high GI foods (preparations from potatoes and rice form a major part of their diet), and yet they are healthy enough. Of course the state of their health could also be due to the high fruit and vegetable content.
Glycemic Index and obesity
Recent studies (reported in Lancet;28364(9436):778-85) indicated that people who consumed higher amounts of carbohydrates and did little or no exercise, tended to put on weight. However, we would like to point out that if people eat lots of pastries and ice creams (low GI) and did little or no exercise, they too would put on weight. So in our opinion it would be wrong to label carbohydrates as “bad”. Glycemic Index (GI) should therefore only be used by diabetics as a means to calculate the effect of a high-carb food on their blood sugar levels.