What is Glycemic Index and Glycemic Load?

These days, Glycemic index has become the most debated topic in the health domain. Before going to the fundamentals of it, let us brush up a little on what are carbohydrates and their relation to glycemic index.

Carbohydrates are biomolecules, when digested they raise your blood sugar levels. All carbohydrate foods are not equal. The time period in which the blood sugar rises depends on the type of the carbohydrate. A simple carbohydrate will be digested quickly and will raise your blood sugar levels instantly. On the other hand, complex carbohydrates will take time to digest and therefore there will be a gradual rise in the blood sugar.

In a country like India where people love to feast on carbohydrates no matter which cuisine they eat, maintaining blood sugar levels, weight maintenance and avoiding overall health issues is a matter of concern. Here the Type of carbohydrates comes into picture.

What is Glycemic Index?

Glycemic index (GI) is the ranking of carbohydrates on a scale of 0 to 100 according to the extent to which they raise your blood sugar levels after consuming a carbohydrate rich meal. Depending on their Glycemic Index, foods are categorized into 3 different categories – Low GI, Medium GI and High GI.

The food that is rapidly digested, absorbed and metabolized and bring about rapid fluctuations in your blood glucose level are called the High Glycemic Index foods. On the other hand, the foods that are digested and absorbed slowly and do not bring an instant spike in your blood glucose and insulin levels are called the Low Glycemic Index foods. The ones in between the both, are the Medium Glycemic Index foods.

What is the GI Range?

Glycemic Index are categorized into 3 categories  :

Ø  Low: 55 or less

Ø  Moderate: 56 – 69

Ø  High: 70 or more

High Glycemic Index (GI) foods (70 or more)

When large quantities of such foods are consumed, the blood sugar levels fluctuate and therefore the insulin level spikes up. Over a period of time, there is an unhealthy state created in the body. The result is that instead of using carbohydrates, the body starts converting them into fats and triglycerides and stores it. LDL levels (bad cholesterol) also may increase with time. Therefore it is not very advisable to eat foods with a High GI regularly. White bread, Sugar, Corn flakes, White Rice, Popcorn, Rice Flakes – all of these come under the high GI category.

Moderate Glycemic Index (GI) foods (56 – 69)

These foods are neither too quick nor too slow in raising the blood sugar levels. They can be eaten occasionally. Foods like quick oats, mangoes, potato, brown rice, all fall under this category.

Low Glycemic Index (GI) foods (55 or less)

Such foods are usually high in fiber and have complex carbohydrates, thus they take a longer time to digest and absorb, thereby do not bring an instant rise in the blood sugar levels. Orange, peach, carrots, peas, legumes and lentils are all low in GI.

6 factors affect the Glycemic index (GI) of a food?

1.  Fat and fiber content of a food tends to lower the GI of the food. More the fat or fiber in a food, lesser will be the GI.

2.  The type of the sugar and starches in the food can affect its Glycemic Index.

3.  Processing a particular food, increases the Glycemic Index of the food.

For example: A fruit will have a lower GI as compared to a fruit juice, because it is processed. 

4.  Ripeness and storage time also affects the GI – the riper a fruit or vegetable is, the higher the GI.

5.  Cooking Method – the time period for which a food is cooked affects the GI. (al dente pasta has a lower GI than soft - cooked pasta)

6.  Different varieties of different foods will have different glycemic index. ( GI changes with different varieties of rice)

What is Glycemic Load?

However, the GI value tells us only about the type of carbohydrates, which is not enough because the quantity of carbohydrates is also important while determining Glycemic Index. There comes the concept of Glycemic Load. 

The Glycemic load (GL)is a better measure of the type of carbohydrates as compared to glycemic index. As it takes into account both the quality and quantity of carbohydrates. The glycemic load is the measure of increase in blood sugar levels after eating one serving of that particular food.

Similar to the glycemic index, the glycemic load of a food can be classified as low, medium, or high:

Low: 10 or less

Medium: 11-19

High: 20 or more

How to calculate Glycemic Load?

The formula for calculating the GL of a particular food or meal is:

Glycemic Load = GI x Carbohydrate (in grams) in per serving / 100

For example, a single apple has a GI of 38 and contains 13 grams of carbohydrates.

GL= 38 x 13/100 = 5

Which means the glycemic Load of apple is low.

How to incorporate low GI foods into your lifestyle?

It is always recommended to prefer low GI foods especially for diabetics. Low GI foods are also a perfect package for weight watchers. They also help to lower the risk of obesity, cardiovascular diseases like atherosclerosis and metabolic syndrome.

7 Tips for maintaining a Healthy Diet and incorporating the GI and GL index into your daily routine:

1. Always have a combination of carbohydrates, proteins and fats in your diet. As the protein and fats tend to lower the overall GI and GL of the recipe.

For example: Instead of having carb rich meal alone, drink milk with it or have a handful of nuts along with it which will reduce the overall GI of the recipe.

2. Have more of whole cereal and pulses instead of having refined and processed ones.

3. Incorporate a lot of veggies in your daily meal to balance the GI.

4. Snack Smart: When it comes to snacking, go for fresh fruits, nuts, yoghurt or sprouts instead of choosing refined flour products like cookies, breads, crackers and biscuits.

5. Portion control is very important. Make sure you do not have a large portion of a carbohydrate rich source at a time.

6. Dairy products like low fat yoghurt, milk or paneer are a healthy option as they are low in GI and help to reduce the overall GI of the meal.

7. Make water your first choice. Avoid sugary drinks and soft drinks as they are empty calories.