Carbohydrates are the energy giving food group and are an essential part of our diet. However, in recent times carbohydrates have been under scrutiny for all the lifestyle diseases it is linked to. One thing we should understand is that not all carbohydrates are equal.
There are two types of carbohydrates -simple and complex. The simple and complex carbohydrates differ in their chemical structure and rate at which they are digested, absorbed and metabolized in the body.
Simple carbohydrates are smaller molecules which are rapidly digested and metabolized whereas complex carbohydrates are larger molecules and are digested slowly causing a slow spike in blood sugar levels. The complex carbohydrates are the ‘Good Carbs’ you need to add to your diet.
Earlier the total carbohydrate was counted to improve sugar response in all foods in a meal plan but now the glycemic index is used. Glycemic index has a wider approach.
It measures the impact of carbohydrate in food on blood sugar levels on consumption. It gives a better idea and more control while planning effective meals and choosing healthier alternatives.
WHAT IS GLYCEMIC INDEX (GI?)
Glycemic index is a ranking system of carbohydrates on a scale from 0 to 100 depending on the blood sugar spike they cause after eating.
In simple terms, the glycemic index measures the rate at which a portion of food causes our blood sugar levels to rise.
The glycemic index classifies the carbohydrate in a portion of food in three categories-
1) Low: 55 or less 2) Moderate: 56 – 69 3) High: 70 or more
Foods with a GI of 55 or less are classified as low glycemic index foods. These foods are digested, absorbed and metabolized slowly causing a lower and a slower rise in the blood glucose levels.
Low glycemic index foods are considered to be pro-health and reduce the risk of type 2 diabetes, heart disease, metabolic syndrome, stroke, depression, chronic kidney disease, the formation of gall stones and aid in weight loss.
Foods with high glycemic index are rapidly digested and metabolized and as a result, cause marked fluctuations in blood sugar levels.
HOW IS GLYCEMIC INDEX MEASURED?
To measure glycemic index a food item is consumed in a portion size that will provide 50gms of carbohydrates. The blood sugar levels are checked after 2 hours of consumption of the food.
While measuring glycemic index the available carbohydrates are considered and carbohydrates that are not digested and metabolized by the human body (i.e. fiber) is subtracted as it directly doesn’t impact the blood glucose levels.
After the blood sugar levels are checked the results are plotted on a graph. The second step of assessing glycemic index of food includes comparing it with a reference food.
One of the two reference foods is generally used for comparison i.e. pure sugar or white bread both having a glycemic index of 100.
GLYCEMIC INDEX (GI) AND GLYCEMIC LOAD (GL)
The rate at which foods will raise blood sugar level depends on three factors: the type of carbohydrates present, nutrient composition and the amount consumed.
However, the GI that doesn’t take into account the amount of food eaten and to solve this problem the glycemic load rating system was developed.
Glycemic load (GL) measure the effect of food on blood sugar levels taking into consideration both the type and quantity consumed.
THE LOW-GI DIET
A number of studies enumerate the positive effects of a Low-Glycemic Index diet on Type 2 diabetes and HBA1C levels. It also improves pregnancy outcomes in women with gestational diabetes (pregnancy induced diabetes).
Other than diabetes, a Low-GI diet helps lower cholesterol levels, reduces risk of heart diseases, protects against several cancers, improves digestive health and is a key factor in losing weight.
A Low-GI diet can answer to insulin resistance seen in PCOS and other hormonal disorders.
