Glycemic Index: A Comprehensive Guide
Discover the significance of the glycemic index in controlling blood sugar levels. Learn how the glycemic Index can help with overall health and diet planning.
Written by
Last updated on 3rd Jul, 2025
The glycemic index is a measure chart of how much a food influences a person's blood sugar levels. Several factors impact a food's glycemic index, including ripeness, nutritional combination, and cooking method. Therefore, the glycemic index helps people make healthier food choices, aiding in weight loss and lowering blood sugar and cholesterol.
This article gives insight into what the glycemic index is, its categories, and its health benefits.
How Does the Glycemic Index Work?
The glycemic index is a statistic that indicates how much certain foods raise blood sugar levels. Here is how the GI (glycemic index) actually works:
Foods are assigned a score from 0 to 100 based on their effect on blood sugar.
Foods with refined carbohydrates and sugar are absorbed quickly, leading to a higher GI.
Foods that are high in protein, fat, or fibre are digested more slowly, resulting in a lower GI.
What are the Glycemic Index Categories?
The glycemic index ranks foods based on how much they raise blood sugar levels after eating or drinking them. There are three categories in the glycemic index, which are as follows:
Low GI: 55 or less
Medium GI: 56 to 69
High GI: 70 or higher
Some examples of foods in each category include:
Low GI: Soy products, beans, fruit, milk, grainy bread, porridge, and lentils
Medium GI: Orange, honey, basmati rice, and wholemeal bread
High GI: white bread, short-grain rice, and potatoes
Health Benefits of Low Glycemic Index Foods
Following a low glycemic diet may offer several health benefits, which are as follows:
Improved blood sugar regulation in persons with diabetes.
Eating a low GI diet may help with weight loss.
It also helps lower liver fat and enzyme levels in persons with non-alcoholic fatty liver.
Glycemic Index and Diabetes
Factors Affecting Glycemic Index of Foods
The glycemic index of a food is affected by multiple factors, including:
Type of Carbohydrate
The type of carbohydrate in a food affects its glycemic index. For example, amylopectin-rich starches are digested and absorbed fast, but amylose-rich carbohydrates are absorbed more slowly.
Processing
The method of processing a food can significantly change its glycemic index. Grinding, rolling, pressing, or chewing a food can disrupt the starch granules and make the food more easily absorbed.
Cooking
The cooking process can influence a food's glycemic index. For example, boiling potatoes breaks down the starch granules, making them simpler to digest. However, cooling cooked potatoes reverses the process, making the part of the starch resistant to absorption.
Acidity
Acidic foods, such as vinegar and lemon juice, slow digestion by delaying stomach emptying and reducing the glycemic index.
Glycemic Index vs Glycemic Load
The glycemic index (GI) and glycemic load (GL) are methods of determining how various meals may influence a person's blood sugar. Multiple factors influence a person's blood sugar levels, including insulin levels, sugar absorption rate, and the amount of glucose in a meal per serving.
The glycemic index (GI) indicates the potential for food to raise blood sugar levels but not the actual blood sugar level.
This is where the glycemic load comes in. It provides a more realistic picture of how food affects blood sugar levels by calculating the real-life influence of diet on blood sugar levels.
For example, watermelon has a high GI of 80, meaning it can quickly raise blood sugar. However, a typical serving of watermelon contains very few carbohydrates (about 6 grams per 100 grams).
Using Glycemic Index in Meal Planning
Individuals can use the glycemic index to plan meals by following these methods:
Choosing Low-GI Foods
One must incorporate more low glycemic index foods into the diet, such as whole grains, legumes, vegetables, most fruits, and dairy products.
Controlling Portion Sizes
Even low glycemic index foods can affect blood sugar if consumed in large quantities. Therefore, controlling portion sizes is crucial.
Intaking Protein
Protein slows down the digestion of carbohydrates and the absorption of glucose into the bloodstream.
Considering the Nutritional Value
One can choose a variety of healthy foods and keep in mind the nutritional value of the whole meal.
Common Misconceptions about Glycemic Index
The glycemic index is a great tool for understanding how foods affect blood sugar levels, but there are several misconceptions as well, which are as follows.
One common misconception is that all low-glycemic index foods are healthy, which isn't always true. For example, some processed foods may have a low glycemic index but those are high in unhealthy fats or sugars.
Another misconception is that glycemic index alone can dictate a balanced diet. In reality, the glycemic index should be considered alongside other nutritional factors like fibre, protein, and fat content, which influence overall health.
Many people also assume that glycemic index values are fixed, but individual responses to foods can vary based on factors such as metabolism, activity levels, and food combinations.
The portion size and preparation methods significantly impact a food’s glycemic index. Understanding these factors can help people make more informed dietary choices rather than relying solely on glycemic index values.
Conclusion
The glycemic index is a valuable tool for understanding how different foods impact blood sugar levels. However, it should be considered alongside other dietary factors to ensure a balanced and nutritious diet.
Focusing on low glycemic index foods can aid in better blood sugar control, weight management, and reducing the risk of chronic conditions like diabetes. Integrating these foods into meal planning helps individuals make informed choices that support sustained health and well-being.
Consult Top Diabetologist
Consult Top Diabetologist
Dr. Liritha C
General Physician/ Internal Medicine Specialist
5 Years • MBBS, MD (GENERAL MEDICINE)
Hyderabad
Apollo 24|7 Clinic, Hyderabad
Dr. Suraja Nutulapati
General Physician/ Internal Medicine Specialist
10 Years • MBBS, MD (Internal Medicine)
Hyderabad
Apollo 24|7 Clinic, Hyderabad
(850+ Patients)
Dr. Lakshmi Sanjitha Kakani
General Physician/ Internal Medicine Specialist
6 Years • MBBS, MD (General Medicine)
Visakhapatnam
Apollo 24|7 Clinic - Andhra Pradesh, Visakhapatnam
Dr. Raveendran Sr
Diabetologist
14 Years • MBBS,MD,D.DIAB,FSM
Chennai
S R Clinic, Chennai
Dr. Mubarak J
Diabetologist
22 Years • MBBS, MD (GENERAL MEDICINE), PG Diploma in Diabetology
Chennai
Jm Diabetes Center, Chennai
(25+ Patients)
