A Beginner’s Guide to the Low Glycemic Diet

The low glycemic diet comes from the concept of the glycemic index.

Research has proven that the low GI diet can result in weight loss, reduce blood sugar levels, and reduce the risk of heart disease and type 2 diabetes.

But, the manner in which foods have been ranked has been criticized for its unreliability and for its failure in reflecting the food’s overall healthiness.

This article will provide a detailed review of a low GI diet, including what it is, the way to follow it, its benefits and drawbacks.

red peppers, parsnips, 2 types of tomatoes, carrots, red apples, cauliflower, spinach, and other produce on a gray surface

What is the glycemic index (GI)?

The carbohydrates found in breads, cereals, fruits, vegetables, and dairy products are an important part of a healthy diet. As you consume any type of card, your digestive system breaks it down into simple sugars, which enter your bloodstream.

All carbs are not the same and have different and unique effects of blood sugar. The glycemic index is a system of measurement that ranks foods according to the effect it has on your blood sugar levels. In the early 1980’s a Canadian professor Dr. David Jenkins created it.

The rate at which varying food increase blood sugar levels are ranked in comparison with the absorption of 50 grams of pure glucose, which is being used a reference food. It has the GI value of 100.

The three GI ratings are:

  • Low: 55 or fewer
  • Medium: 56–69
  • High: 70 or more

The preferred food would be one with a low GI value. It gets digested and absorbed slowly, and causes a slower and smaller rise in the blood sugar levels.

On the contrary, one must limit foods with high GO value. They get digested and absorbed quickly, which causes a rapid rise and fall in the blood sugar levels.

Foods are given a GI value only if they have carbs. So, food that do not have GI cannot be found on GI lists. Examples of these are:

  • beef
  • chicken
  • fish
  • eggs
  • herbs
  • spices

Factors that affect the GI of a food

Several factors can influence the GI value of a food or meal. It includes:

  • The kind of sugar it has. A common misconception that all kinds of sugars have a high GI. The GI of sugar can range from as low as 23 for fructose to up to 105 for maltose. Thus, the GI of a food is partly dependent on the kind of sugar it has.
  • Starch’s structure. The carb, starch has two molecules — amylose and amylopectin. While amylose is difficult to digest, amylopectin is easy to digest. Foods that have a higher amylose content will have a lower GI.
  • How refined the carb is. When foods undergo processes like grinding and rolling, their amylose and amylopectin molecules are disrupted and its GI increases. So, the more processed a food is, the higher its GI.
  • Nutrient composition. If you add protein or fat to a meal, it can slow digestion and help reduce the glycemic response to a meal.
  • Cooking method. The preparation and cooking techniques can affect the GI too. The longer a food is cooked, the faster its sugars will be digested and absorbed, raising the GI.
  • 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.

The amount of carbs is also important

The rate at which foods increase blood sugar levels are dependent on three factors: the kind of carbs it contains, its nutrient composition, and the amount you eat. But, the GI is a relative measure and does not take into account the amount of food eaten. This is the reason it is highly criticized.

The Glycemic load measurement was developed as a solution to this problem. It is a measurement of the way a carb affects blood sugar levels and takes both the type (GI) and quantity (grams per serving) into account.

GL also has three classifications:

  • Low: 10 or fewer
  • Medium: 11–19
  • High: 20 or more

However, GI is still the most important element to consider when you follow the low GI diet.

However, an Australian nonprofit, the Glycemic Index Foundation raises awareness about the low GI diet, and suggests that people must monitor their GL and should try to keep their overall daily GL under 100.

If not, the easiest way to get a GL under 100 is to select low GI foods as and when possible and eat them in moderation.

Low GI diet and diabetes

Million of people worldwide are affected by the complex disease, diabetes. The ones who have it are unable to effectively process sugar, which makes it tough to maintain healthy blood sugar levels.

Having a good control over blood sugar can prevent and delay the onset of complications which include heart disease, stroke, and damage to the nerves and kidneys.

In several studies, it has been shown that low GI diets reduce blood sugar levels in people who have diabetes.

A review of more than 50 studies have the conclusion that diets with low GI led to a reduction if hemoglobin A1C, body weight, and fasting blood sugar levels in people who have prediabetes or diabetes.

Some researches have related high GI diets with a high risk of developing type 2 diabetes. One study found that people with the highest GI diets had about 33% greater risk of developing type 2 diabetes compared to ones who consumed lowest GI diet.

A review of 24 studies showed that for every 5 GI points, there is an increase of 8% in risk of developing type 2 diabetes.

Following a low GI diet can also improve the pregnancy outcomes in women who have gestational diabetes, a kind of diabetes that occurs during pregnancy.

Also, low GI diets have shown to lower the risk of macrosomia by 73%. It is a conditions in which the newborns have a birth weight of over 8 pounds and 13 ounces. It has associated with several short-and long-term complications for both the mother and baby.


Other benefits

A low GI diet is also known to have other health benefits:

  • Better cholesterol levels. A study has shown that lower GI diets reduce the total cholesterol by 9.6% and LDL cholesterol by 8.6%. The latter is associated with a high risk of heart disease and stroke.
  • Helps lose weight. Evidence relates low GI diets with fat loss. But, more research is needed to confirm whether low GI diets are effective for long-term weight loss.
  • May lower the risk of cancer. Studies show that people who have high GI diets are more probable to develop certain types of cancer, which includes endometrial, colorectal, and breast cancer, compared with people on low GI diets.
  • May lower the risk of heart disease. Research has strongly links high GI and GL diets with an increased risk of heart disease

Foods to eat on the low GI diet

You do not have to count calories or your protein, fat, or carbs, when you are on the low GI diet. You just have to change the high GI foods for ones with low GI alternatives.

There are several healthy and nutritious foods that you can choose from. You must build your diet around the given low GI foods:

  • Bread: whole grain, multigrain, rye, sourdough
  • Breakfast cereals: steel cut oats, bran 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, and more
  • Pasta and noodles: pasta, soba noodles, vermicelli noodles, rice noodles
  • Rice: basmati, Doongara, long grain, brown
  • Grains: quinoa, barley, pearl couscous, buckwheat, freekeh, semolina
  • Dairy and dairy replacements: milk, cheese, yogurt, coconut milk, soy milk, almond milk

The given foods have few or no carbs and therefore don’t have a GI value. They can be included in your low GI diet:

  • Fish and seafood: including salmon, trout, tuna, sardines, and prawns
  • Other animal products: including beef, chicken, pork, lamb, and eggs
  • 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, dill, salt, and pepper

Foods to avoid on the low GI diet

You do not have to avoid anything strictly when you are on a low GI diet. You simply have to replace the high GI foods with their low GI alternatives as much as you can.

  • Bread: white bread, bagels, naan, Turkish bread, French baguettes, Lebanese bread
  • Breakfast cereals: instant oats, Rice Krispies, Cocoa Krispies, Corn Flakes, Froot Loops
  • Starchy vegetables: Désirée and Red Pontiac potato varieties, instant mashed potatoes
  • Pasta and noodles: corn pasta and instant noodles
  • Rice: Jasmine, Arborio (used in risotto), Calrose, medium-grain white
  • Dairy replacements: rice milk and oat milk
  • Fruit: watermelon
  • Savory snacks: rice crackers, Corn Thins, rice cakes, pretzels, corn chips
  • Cakes and other sweets: scones, doughnuts, cupcakes, cookies, waffles, cakes
  • Other: jelly beans, licorice, Gatorade, Lucozade

A sample low GI menu for 1 week

Here is a sample menu that shows what a week on the low GI diet might look like. It also has some recipes from the Glycemic Index Foundation.

You can adjust this or add low GI snacks according to on your own needs and preferences.


  • Breakfast: oatmeal made with rolled oats, milk, pumpkin seeds, and chopped, fresh, low GI fruit
  • Lunch: chicken sandwich on whole grain bread, served with a salad
  • Dinner: beef stir-fry with vegetables, served with long grain rice


  • Breakfast: whole grain toast with avocado, tomato, and smoked salmon
  • Lunch: minestrone soup with a slice of whole grain bread
  • Dinner: grilled fish served with steamed broccoli and green beans


  • Breakfast: omelet with mushrooms, spinach, tomato, and cheese
  • Lunch: salmon, ricotta, and quinoa cups with a salad
  • Dinner: homemade pizzas made with whole wheat bread


  • Breakfast: smoothie with berries, milk, Greek yogurt, and cinnamon
  • Lunch: chicken pasta salad made with whole wheat pasta
  • Dinner: homemade burgers with beef patties and vegetables on whole wheat rolls


  • Breakfast: fruity quinoa porridge with apple and cinnamon
  • Lunch: toasted tuna salad sandwich on whole wheat bread
  • Dinner: chicken and chickpea curry with basmati rice


  • Breakfast: eggs with smoked salmon and tomatoes on whole grain toast
  • Lunch: whole grain wrap with egg and lettuce
  • Dinner: grilled lamb chops with greens and mashed pumpkin


  • Breakfast: buckwheat pancakes with berries
  • Lunch: brown rice and tuna salad
  • Dinner: beef meatballs served with vegetables and brown rice

Healthy low GI snacks

If you get hungry between meals, these are some healthy low GI snack ideas:

  • a handful of unsalted nuts
  • a piece of fruit with nut butter
  • carrot sticks with hummus
  • 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
  • a hard-boiled egg
  • low GI leftovers from the night before

Drawbacks of the low GI diet

Along with the innumerable benefits, low GI diet also has a number of drawbacks.

The primary drawback is that it does not give a full picture. It is necessary to consider the fat, protein, sugar and fiber of food, irrespective of its GI.

For instance, the GI of frozen french fries is 75. However, some kinds of baked potato, a healthier alternative, have a GI of 93 or more.

Also, there are a lot unhealthy low GI foods, like a Twix bar (GI 44) and ice cream (GI 27–55 for low fat versions).

Another drawback is that the GI looks at the effect of a single food on blood sugar levels. However, most foods are eaten as a part of a larger mixed meal, which makes it difficult to predict its GI.

GI does not consider the number of carbs eaten. This is another important factor in the determinations of its effect on your blood sugar levels.

For instance, watermelon has a high GI of 72–80 and thus, is not the best option when following a low GI diet. But, watermelon has a low carb content, and has under 8 grams of carbs per 100 grams. Also, just a single serving of watermelon has a low GL of 4–5 and a little effect on blood sugar levels.

This show that just using GI probably is not the best predictor of blood sugar levels. It’s vital to consider the carb content and GL of a food.

The bottom line

A diet on low glycemic foods is all about switching the high GI foods for ones with lower GI.

It has several potential health benefits, like a reduction in blood sugar levels, help in weight loss, an lower risk of heart disease and type 2 diabetes.

But, this diet has several drawbacks.

It is important that you consume a healthy, balanced diet consisting of various whole and unprocessed foods, irrespective of their GI.