Glycemic index is a measure that rates carb containing food by how much they affect the blood sugar levels as compared to a standard carb food – mostly glucose or white bread.
When the carb foods are ingested, the digestive system breaks down the starch to give energy. Blood glucose levels increase due to this process. Glycemic response is the rate at which a carb enhances the blood glucose level. Different factors affect this speed of increase in blood glucose level ..like, how the food is cooked, how much carb is ingested etc.
The glycemic response helps in deciding the glycemic index of carb rich foods. The food products, which are metabolized easily and increase blood sugar levels quickly, have a high glycemic index. If a carb rich food has a GI of 70 or more than that, then it is considered high glycemic index food.
It is always advisable to select a low or medium GI food over high GI food. But still, it wouldn’t be very wise to eliminate all the high glycemic index foods totally from our daily diet. Because many such high GI foods also contain important nutrients necessary for our body.
So, while selecting a diet:
A food should be considered for its overall nutritive value, taking into account the fiber content, vitamins, minerals etc. Fro example, white potatoes have a high GI, but still it should not be absolutely cut off from diet, as they have other nutritional ingredients which are important for our body.
Combining a high glycemic index food with a low GI food makes it a medium GI diet and reduces the high glycemic response to some extent. For ex. Cornflakes (high GI) with some All bran(low GI) and strawberries (low GI)
Processed and refined carb foods have a high GI and are low in fiber and nutrients. So it is better to reduce intake of such food.
White bread has a high GI, so a whole grain or oat bran bread should be chosen for healthier diet.
Potatoes have a high GI, but if eaten cold, in a salad, there is some reduction in GI
Common high glycemic index foods:
- Watermelon 72
- Instant mashed potatoes 70
- Instant rice 46
- Baked white potatoes 85
- Corn flakes 84
- Dried dates 103
- Parsnip 97
- Rice krispies 82
- White bagel 95
- French fries 75
- Jelly beans 80
- Soda crackers 77
- White bread 70
High glycemic index foods give a quick increase in blood glucose levels. These high blood glucose levels are called ‘glycemic spikes’, which are observed after a high GI meal. Such spikes result in enhanced insulin levels and the oxidative damage to the vasculature is also more. These effects increase the risk of diseases like type 2 diabetes mellitus and coronary heart disease.
Earlier this increase in glycemic levels following a diet of high GI food was thought to be a cause of problem only in diabetes patients. But now studies indicate that such glycemic spikes can enhance the chances of atherosclerosis even in people not suffering from diabetes.
According to a study report ( University of Sydney), a regular breakfast of white bread and cereals with high sugar content (if taken for years) can increase the risk of heart disease, diabetes and also cancer, in the person.
Studies regarding effects of high GI products in human beings have their own difficulties, because distinguishing effects of high GI products from other factors like fiber content etc is not very precise. Studies of these foods on animals indicate that high GI food increases chances of obesity and thus risk of chronic diseases.
Advantages of high glycemic index food:
Although low GI foods are preferred for weight loss and overall good health, still, high GI foods do have their own advantages – like rich in nutrients.
If, after a heavy exercise, there is a need of increasing dropped blood glucose levels, then high GI foods provide the required energy quickly. Similarly, if there is a risk of hypoglycemia in a diabetes patient, a high GI food can correct it with ease.
A study has shown a regular diet of high GI can increase the chances of fatty liver disease in obese children. They are at a risk of developing liver disease in adulthood.
Fatty liver—fat in excess amount are stored in liver resulting in inflammation of liver and the liver can turn hard gradually. This may lead to liver failure.