What is Glycemic index and why you should know about it

Blood sugar levels in our body is determined by what we eat,when we eat and how much we eat and is regulated by a hormone called Insulin. In a normal person,insulin hormone regulates the post prandial blood sugar that is roughly 1-2 hours after a meal and keeps it under control.

If you have Diabetes, high blood sugars can be a wake-up call, telling you that it is the time to start making healthier food choices.

In simple language,the carbohydrate component of the food breaks down in the stomach and contributes towards the blood sugar levels.Excess protein and fats too convert to blood glucose eventually by various pathways.

Complex carbohydrates which contains fibers and starches made of complex structures gets broken down and absorbed slowly in the stomach and the blood sugar levels rise steadily. These foods are better choices for people with Diabetes, because they do not cause spikes in blood glucose levels which cause damage to your organs in the long run. Simple sugars like sucrose,fructose are broken down easily and increase blood sugar quickly causing harm.

What is Glycemic Index?

Glycemic Index or GI, measures how a carbohydrate-containing food raises blood glucose.

GI can be classified into-

  • Low GI-Foods which do not increase the blood sugar levels too much post meal.
  • Higher GI-Foods which increases blood sugar levels considerably post meal.

Why is Glycemic Index important?

In diabetes patients,the regulation of blood sugar levels are impaired and there is a unregulated sugar levels.These blood sugar levels have a direct association with which food is consumed.As mentioned earlier,carbohydrates after consumption contribute towards the blood sugar levels and hence  glycemic index of a carbohydrate is an important factor in determining the post prandial blood sugar levels.

Hence for diabetics it is advised to include lower glycemic index foods to the diet on the contrary high glycemic index foods are told to be avoided as they increase blood sugar levels quickly.

Research shows that both the amount and the type of carbohydrate in food affect blood glucose levels. Studies also show that the total amount of carbohydrate in food, in general, is a stronger predictor of blood glucose response than the GI.

What affects the glycemic index of food?

As a general rule fiber lowers the GI and simple sugars have higher GI.

  • Ripeness and storage time — the more ripe a fruit or vegetable is, the higher the GI and increase in storage time increases GI
  • Processing — juice has a higher GI than whole fruit; mashed potato has a higher GI than a whole baked potato,  whole wheat bread has a lower GI than white bread.Processed potato chips,snacks made of rice and potato have higher GI.
  • Cooking method — Food cooked for longer duration tends to break into simple sugars and have lower GI.
  • Variety —  Brown rice has lower GI than white rice.

The Glycemic Index of a food is different when eaten alone than it is, when combined with other foods. Include Higher GI food with lower GI food items to balance out the meal.

Example of foods according to Glycemic index

Low Glycemic Index Foods

  • Oatmeal, oat bran, muesli
  • Barley,ragi,millets,bajra
  • Sweet potato, corn, yam, beans, peas, legumes and lentils,chickpeas
  • Most fruits, non-starchy vegetables and carrots
  • Whole wheat, rye and pita bread
  • Brown, wild or basmati rice

High GI

  • White bread,maida
  • Corn-flakes,puffed rice snacks,bran flakes,instant oat
  • Short grain white rice, rice pasta, macaroni,pizza,cheese
  • Potato, pumpkin
  • Rice cakes, popcorn,  crackers,cookies,candies,donuts and cakes
  • pineapple,mango

There is no best meal plan best for diabetics.So it is important to follow a meal plan that is tailored according to the requirements. Better food choices and lifestyle changes keep the blood sugar levels steady.

Research indicates Glycemic Index is a tool that helps with Diabetes management. Combined with carbohydrate counting, it may provide an additional benefit for achieving blood glucose goals for diabetics and pre diabetics.

Discuss with your doctor/nutritionist about the various glycemic indices in the food of your choice and tailor it to your diet by using this important tool.

-Dr Prerna Gaur






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