Low-Glycemic index diet: What’s behind the claims?

Description: Learn about the low-glycemic index diet and an eating plan that is based on how food affects blood sugar levels.

A low-glycemic index (low-GI) diet is an eating plan that is focused on how foods impact blood sugar, also known as blood glucose level.

The glycemic index rates foods from 0 to 100. Foods at the low end of the range have minimal influence on blood sugar levels. The foods at the top of the scale have a significant impact on blood sugar levels.

The glycemic index is the primary guidance for meal planning in a low GI diet. People may also use the glycemic index as one of several tools to help them make food and meal decisions.


The purpose of a low-GI diet is to select meals that are less likely to boost blood sugar levels.

Why you should eat a low-GI diet

You may choose to follow a low-GI diet because:

  • Want to lose or maintain a healthy weight?
  • Need assistance with meal planning and eating healthier meals?
  • As part of a diabetic treatment plan, you may require assistance in preventing blood sugar levels from being too high or too low.
  • Want to reduce your chances of developing diabetes or heart or blood vessel disease?

The Glycemic Index

The glycemic index is intended to serve as a food-selection aid for diabetics. The Sydney University Glycemic Index Research Service in Sydney, Australia, maintains a worldwide database. The database contains the findings of dietary research conducted all across the world.

Grasp low-GI diets requires a fundamental understanding of carbs and blood sugar.


Carbohydrates, commonly known as carbohydrates, are a type of nutrient found in diet. Sugars, starches, and fibre are the three primary types. Carbohydrate sugars and starches are broken down by your body. They degrade into glucose, a form of sugar. This sugar enters the circulation and serves as the primary source of energy for your body’s cells. Fiber travels through your digestive tract undigested.

Two major pancreatic hormones aid in glucose regulation in the circulation. Insulin transports glucose from the blood into the cells. When blood sugar levels are low, the hormone glucagon aids in the release of glucose held in the liver. This mechanism aids in keeping the body fed and blood sugar in check.

Many different factors in food influence how quickly glucose enters the bloodstream.

Understanding GI numbers

The glycemic index evaluates foods based on their influence on blood sugar levels. A low-GI diet includes foods with low GI levels. The categories are as follows:

  • Low GI: 1 to 55
  • Medium GI: 56 to 69
  • High GI: 70 and higher

Researchers frequently compare the impact of consuming a food with the effect of eating sugar on blood sugar levels in order to award a rank, often known as a GI value. The parallel is sometimes drawn to eating white bread. To evaluate the GI value of cantaloupe, for example, 10 or more healthy persons consume enough melon to digest 50 grammes of total carbs. Each participant will get roughly one medium cantaloupe. Their blood sugar levels are measured many times during the following two hours. The same ten persons consume 50 grammes (12 teaspoons) of sugar on another day. Their blood sugar levels are checked multiple times throughout the course of two hours.

Limits of GI values

The glycemic index does not take into account how much of a food you are likely to consume throughout a meal. You wouldn’t eat a full medium-sized watermelon at once, for example.

To focus on this issue, researchers devised the concept of glycemic load (GL). This value represents the influence on blood sugar levels when a common portion of meal is consumed. For example, you may have one-third of a medium-sized cantaloupe in a single meal. That much cantaloupe has a GL value of 11 or less.

The table of GI values at Sydney University also contains GL values. The GL values are classified as follows:

  • Low GL: 1 to 10
  • Medium GL: 11 to 19
  • High GL: 20 or more

Other issues

A GI value provides no extra nutritional information. Cantaloupe, for example, has a medium to high GI and a medium GL score. However, it is high in vitamin C, beta carotene, and other essential elements. Whole milk has a low glycemic index (GI) and a low GL value. However, it is heavy in fat and calories. As a result, it may not be a good choice for weight loss or control.

The published GI database does not contain an exhaustive list of foods. It is instead a list of meals that have been investigated. Many healthy foods with low GI levels may be missing from the database. There are also highly processed items on the list, which may be less nutritious than unprocessed foods. Furthermore, certain meals with low GI scores may be deficient in nutrients.

The GI value of every dietary item is determined by a variety of variables. It is important to consider how food is cooked and processed. Furthermore, GI levels for the same meals might vary. As a result, the values may not be applicable to all meal options.

Diet details

If you follow a low-GI diet, your foods with carbs are mostly limited to choices with low values. You usually will avoid foods with high values. Examples of foods with low, middle and high GI values are:

  • Low GI: Green vegetables, most fruits, raw carrots, kidney beans, chickpeas, and lentils are all good choices.
  • Medium GI: Sweet corn, bananas, raw pineapple, raisins, cherries, oat breakfast cereals, and multigrain, whole-grain wheat, or rye bread are all good choices.
  • High GI: Potatoes, white rice, and white bread.

Foods with slow carbohydrates or quick carbs may be mentioned in commercial low-GI diets. This is because meals with a low GI rating take longer to digest and absorb. High-value foods are absorbed in a shorter period of time.


The outcomes of low-GI diet studies have been mixed. In general, they have found that a low-GI diet may be beneficial for:

  • Weight loss
  • Blood pressure reduction
  • Reduced total cholesterol levels
  • Diabetes management is being improved.
  • reducing the risk of diabetes, heart disease, and blood vessel disease

The advantage of the diet may be connected to nutrient-rich meals and high-fiber foods, according to the researchers. It is possible that the total nutritional content of the diet is more relevant than the GI rating of individual single item.

In conclusion

A low go diet may help you lose weight or maintain a healthy weight. It may aid in the management of a diabetic regimen. It may reduce the risk of diabetes, heart disease, and blood vessel disease.

The glycemic index might be one tool, rather than the primary instrument, for assisting you in making better meal choices. The Dietary Guidelines for Americans propose emphasizing healthy eating habits and nutrient-dense foods.

Making consistent healthy choices throughout time is what a good eating pattern entails. Foods that meet that pattern differ. They contain a wide range of fruits and vegetables that are high in vitamins, minerals, and fibre. Whole-grain meals abundant in fibre and other nutrients are also part of a healthy dietary pattern. Beans, lentils, seafood, low-fat dairy products, and lean meats are all excellent alternatives.