Understanding Glycaemic Index and Glycaemic Diet

A Beginner’s Guide – Glycaemic Index And Glycaemic Diet

Oct 09, 2022Imtiaz Hami


We have all heard that low glycaemic index (GI) foods are better for you and many doctors now advice their patients to have food products low in GI – what does all this really mean? The glycaemic index (GI) is obtained by measuring the effect that a carbohydrate containing food has on blood sugar levels, compared to the effect of the same amount of pure sugar, on blood sugar levels.

The term was introduced in 1981 by David J. Jenkins, a Canadian professor. It is useful for quantifying the relative rapidity with which the body breaks down carbohydrates. It takes into account only the available carbohydrate (total carbohydrate minus fiber) in a food. Glycemic index does not predict an individual’s glycemic response to a food, but can be used as a tool to assess the insulin response burden of a food, averaged across a studied population.

Factors affecting the glycaemic index

There are various factors that affect the GI of a food. These include the types of sugar and starches in the food, the way it is prepared, and it’s fat and fibre content. How rapidly the food product is digested and absorbed is very important in determining the GI. Generally, foods with a low level of starch and high in fibre tend to have a lower GI level – ie whole grains, oats and barley.

Let’s break it down for better understanding. The index typically categorizes foods as low, medium, and high. The following ranges are usually applied to determine the GI of a particular food:

  • Low GI – 55 or less.
  • Medium GI – 56 to 69.
  • High GI – 70 or more.
  • Foods with a low GI means that they cause a slower and lower rise in blood sugar levels. These include mixed-grain and oat breads, fruit, barley, pasta, noodles, beans, sweet potatoes, green peas and milk.
  • Foods with a high GI means that they cause a faster and higher rise in blood sugar levels. High GI foods include white bread, steamed white rice, chips and coffee.

A number of factors can influence the GI value of a food or meal, including:

  • Sugar- There’s a misconception that all sugars have a high GI. The GI of sugar ranges from as low as 23 for fructose to up to 105 for maltose. Therefore, the GI of a food partly depends on the type of sugar it contains.
  • Starch- Starch is a carb comprising two molecules — amylose and amylopectin. Amylose is difficult to digest, whereas amylopectin is easily digested. Foods with a higher amylose content will have a lower GI.
  • Carbohydrate– Processing methods such as grinding and rolling disrupt amylose and amylopectin molecules, raising the GI. Generally speaking, the more processed a food is, the higher its GI.
  • Nutrient composition– Adding protein or fat to a meal can slow digestion and help reduce the glycemic response to a meal.
  • Cooking method– The more cooked, or over cooked, a food, the more its cellular structure is broken, with a tendency for it to digest quickly and raise blood glucose more
  • Ripeness– Unripe fruit contains complex carbs that break down into sugars as the fruit ripens. The riper the fruit, the higher its GI. For example, an unripe banana has a GI of 30, whereas an overripe banana has a GI of 48

More importantly, the glycemic response is different from one person to another, and also in the same person from day to day, depending on blood glucose levels, insulin resistance, and other factors.


It is a meal plan which is built around the effects of the different foods that we consume and how they impact our blood sugar and glucose levels. The diet helps diabetic people keep a track of their blood sugar level and has also caught up with individuals who are determined to achieve a healthier weight.

Foods to eat on the low GI diet

There’s no need to count calories or track your protein, fat, or carbs on the low GI diet. Instead, the low GI diet involves swapping high GI foods for low GI alternatives.

  • Bread: whole grain, multigrain, rye, sourdough
  • Breakfast cereals: steel cut oats, corn flakes
  • Fruit: apples, strawberries, apricots, peaches, plums, pears, kiwi, tomatoes, and more
  • Vegetables: carrots, broccoli, cauliflower, celery, zucchini, and more
  • Starchy vegetables: sweet potatoes with an orange flesh, corn, yams, winter squash
  • Legumes: lentils, chickpeas, baked beans, butter beans, kidney beans
  • Pasta and noodles: pasta, soba noodles, vermicelli noodles, rice noodles
  • Rice: basmati, long grain, brown
  • Grains: quinoa, barley, pearl couscous, buckwheat, semolina
  • Dairy and dairy replacements: milk, cheese, yogurt, coconut milk, soy milk, almond milk
  • Nuts: such as almonds, cashews, pistachios, walnuts, and macadamia nuts
  • Fats and oils: including olive oil, butter, and avocado
  • Herbs and spices: such as garlic, basil, salt, and pepper

Healthy low GI snacks

If you find yourself hungry between meals, here are a few healthy low GI snack ideas:

  • A handful of unsalted nuts
  • A piece of fruit with nut butter
  • Carrot sticks with hummus
  • Low GI and high protein Khakhra
  • A cup of berries or grapes served with a few cubes of cheese
  • Greek yogurt with sliced almonds
  • Apple slices with almond butter or peanut butter


  • Low Cholesterol levels: The low GI diets reduce total cholesterol by 9.6% and LDL (bad) cholesterol by 8.6%. When combined with a high fibre diet, a low glycaemic diet will help lower cholesterol levels, especially low-density lipoproteins or bad cholesterol. LDL cholesterol is also associated with an increased risk of heart disease and stroke.
  • Weight Loss: It is common knowledge that cutting down on sugar and ditching unhealthy sweet things will help you lose the kilos and the inches quicker and also help you maintain a more healthy, active and fit lifestyle. Obesity and weight gain are usually a direct result of consuming grains, starches, and sugars. A low glycaemic diet steers clear from all these foods helping you shed a significant amount of weight. The diet also propagates foods that are fibre heavy and fibre found in most of foods can help you feel fuller thereby suppressing appetite and curbing hunger pangs.
  • Reduced risk of cancer: Some studies suggest that people who consume high GI diets are more likely to develop certain types of cancer, including endometrial, colorectal, and breast cancer, compared with people on low GI diets.

Blood Sugar Control: It has been clinically observed that people who tend to consume a low glycaemic diet also tend to have better control over their blood sugar levels. Foods that are measured lower on the glycaemic index are also slowly digested and metabolized by the body thereby releasing glucose into the bloodstream steadily and gradually. This keeps the blood sugar levels in a safe range by preventing unusual and unnatural spikes and drops from occurring.

Following a low glycemic diet may offer several health benefits, as it could help balance your blood sugar levels, lower your cholesterol, and increase short-term weight loss.

“The food you eat can be either the safest and most powerful form of medicine or the slowest form of poison.” — Ann Wigmore


Please do share your valuable feedback we are open for any comments

If you like this blog, don’t forget to share it!

Related articles