GI Diet

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GI Diet


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Lose weight the scientific way with the GI Diet, a nutritionally balanced and healthy diet for overall health!


About the GI Diet

The Glycemic Impact, Glycemic Diet or simply the GI Diet, was created by Rick Gallop, former president of the Heart and Stroke Foundation of Ontario, who claims that the “GI Diet is a simple and healthy way to lose weight without going hungry.” Yep, you read that right- “without going hungry”. Because, really, how many diets can truly claim that and back it up? Turns out that this diet may be able to, as its founder, Gallop, had tried many diets to counter his own weight gain issues when he discovered the Glycemic Index or GI as an answer to all weight related problems.

Seafood, Poultry and Lentils

Seafood, poultry and legumes are foods that can be consumed with no restriction as a part of the GI Diet

According to Gallop, dieters usually give up on diets because:

  • They feel deprived or hungry when following a particular diet.
  • Diets are too complex as they involve counting and measuring calories, grams, points, etc.
  • The diets don’t seem too healthy.

Yes, finally someone gets it and we can feel less like failures now! Turns out that these problems are faced by dieters around the world, to which the GI diet may be an answer. But to understand what the GI diet is, let’s first understand what the “GI” in GI diet is. The concept of Glycemic Index or GI was created in 1981 by Dr David Jenkins who was a professor of nutrition at University of Toronto. GI is the speed at which foods are broken down to make glucose, which is the source of energy for the body. The foods that have a high GI break down very quickly leaving you hungry in a short time, while low GI foods break down more slowly and keep you feeling full for a longer time. He developed a scale known as the Glycemic Index, which are essentially foods that are ranked on basis of the effect they have on the blood sugar levels.    The GI Diet was originally developed for patients with diabetes, but is now being promoted as a weight loss diet. The diet claims to be based on scientific principles that help to stabilize blood sugar levels and fat loss. The GI Diet claims that it isn’t a “quick fix” or “fad” diet to lose weight quickly but an effective way to lose weight and keep it off long term.

How Does the GI Diet Work?

The GI Diet works on the principle of categorizing various foods on basis of their GI and encourages you to eat foods that have a low GI. Just like traffic lights, the GI Diet recommends foods that you can consume by listing all the foods in the three colors:

  • Red Light Foods: Foods to avoid if you want to lose weight
  • Green Light Foods: Eat-as-much-as-you-like foods
  • Yellow Light Foods: Foods to be eaten occasionally

By the above categorization, foods having a high GI are mostly those made from white flour, heavily processed due to which all the nutrients have been stripped away. On the other obvious hand, low GI foods are nutrient dense and are good for health, such as vegetables, fruits, whole grains, lean meat and fish, legumes and low-fat dairy.   The focus of the GI Diet is consuming a mix of proteins, fats and low-GI carbs. On the GI Diet, 40 percent of the total calories are contributed by complex, healthy carbs such as fruits, vegetables and whole grains, 30 percent of calories from protein sources such as chicken, beef, tofu, and eggs, and the balance 30 percent from good fats such as olive oil, nuts and avocados. The objective of the GI Diet plan is to include all food groups in each meal to create nutritional balance and prevent fluctuations in blood sugar levels.

Nuts DASH Diet

30% of your calories should come from healthy fats sources like nuts

So how can you lose weight by following the GI Diet? It’s simple! When you eat meals that have a low GI, you feel less hungry and you can control your hunger pangs by eating foods that satiate you, thereby reducing the desire to overeat or snacking1. This helps to reduce your calorie consumption thereby helping to shed those unwanted pounds. The point of the GI Diet is that by following the diet, you will not feel deprived or go hungry.

What Is Glycemic Index?  

Like we said, glycemic Index or GI is the ranking of foods that contain carbohydrates based on the effect they have on your blood sugar level. The GI values range from 0-100 and use glucose as the reference point. Glucose has a GI value of 100. The effect of other foods on the blood sugar levels are compared with this. In simple words, the GI index indicates whether the food we consume raises the blood sugar levels significantly, moderately or a little. Foods that have a slow and small effect on the blood sugar value have a low GI value. On the other hand, foods causing a considerable and rapid rise in the blood sugar have high GI value.   GI values are divided into three groups:

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


Whole Grains

Whole grains are low in GI


Relationship Between GI and Weight

Foods that have a low GI value release sugar into the blood very slowly. This provides the body with a slow and steady supply of energy and keeps you satiated for longer periods of time. So you are less likely to snack and this helps you lose weight2, meaning that these guys are the good guys! On the contrary, foods that have a high GI value result in a rapid but brief rise in blood sugar. This leaves you tired and lacking in energy and you begin feeling hungry within a short time of eating, causing craving for food and hunger pangs. If this repeats frequently, you end up overeating which causes weight gain3.   Eating plenty of foods with high GI value has disadvantages:

  • The energy rush that you get by eating high GI foods does not last long and is soon followed by an energy crash. This makes you feel hungrier and you end up eating more.
  • As soon as you consume high GI foods, your body will have plenty of readily available energy, which is then used by the body first rather than other energy sources such as fat. This makes it very difficult for you to lose weight.


Factors Affecting the GI of Food

There are many factors that affect the GI value of food.

  • The overall nutrient content of a food will affect its GI. For example, protein4 and fat5 content in food affect the absorption of carbohydrates. For example, chocolate which has a high fat content has a low GI value. Also, whole milk also has a low GI value as it is loaded with fat and protein.
  • The variety and ripeness of fruit, the manner in which food is cooked, and the amount of processing food undergoes, are all factors that affect the GI value of food.
  • The carbohydrate structure also impacts the GI value. For example, processed instant oatmeal has a higher GI value than rolled oats. As a result of processing, the starch in the instant oats is broken down by the digestive enzymes in the body more quickly and enters the bloodstream more swiftly. Other foods that are packed with fiber have a low GI value as the fiber acts as a barrier and slows down the absorption of carbohydrate into the bloodstream6.


Assortment of Fruits

Choosing fresh fruits over processed juices or pulps is what the GI Diet promotes


What Is Glycemic Load?

Glycemic Load (GL) is a more accurate representation of how food will affect your blood sugar level. GL is the amount of carbohydrates in the food and how much each gram of it will raise your blood sugar level. In order to find a food’s GL, multiply its GI value by the number of carbohydrate grams in a serving, and then divide that value by 100.

  • Low GL: 1-10
  • Moderate GL: 11-19
  • High GL: 20 or higher

People suffering from diabetes should have food with GL values that are as low as possible.

GI Diet vs. Atkins Diet

Reading about the GI diet probably reminded you of another somewhat similar diet- the Atkins diet. Though both center around carbs, the Atkins diet bans consumption of most carbs, especially in the early stages of the diet. On the other hand, the GI Diet actively encourages you to eat many carbs, especially antioxidant-rich vegetables and fruits. The GI Diet is also rich in fiber which helps to prevent constipation7. Since the carbs consumption is not restricted to a large extent by the GI Diet, you won’t have problems such as headaches and bad breath, side effects associated with the Atkins Diet. The GI Diet follows a meal plan that is low-fat, especially the saturated variety of fats. Finally, the GI Diet is very convenient and easy to follow even if you are a vegetarian, unlike the snobby Atkins Diet!

Healthy Fruits and Vegetables

The GI Diet is vegetarian friendly unlike the Atkins Diet


What’s on the Menu?


Green Light Foods



Fruits like grapefruit are a part of the Green Light foods allowed in the GI Diet


Yellow Light Foods

  • Breakfast Cereal: Bran buds, mini wheats, nutri-grain, shredded wheat, and porridge oats
  • Bread: Croissant, hamburger bun, pita (white), and wholemeal rye
  • Vegetables: Beetroot
  • Snacks and Sweet Foods: Digestives, blueberry muffin, and honey
  • Legumes: Beans in tomato sauce
  • Fruits: Mango, sultanas, bananas, raisins, papaya, figs, and pineapple
  • Staples: Rice, couscous, cornmeal, taco shells, gnocchi, potatoes (canned), rice vermicelli, baked potatoes, and wild rice
  • Dairy: Ice cream



Honey is a Yellow Light food in the GI Diet that is a great replacement of sugar


What’s off the Menu?


Red Light Foods

  • Breakfast Cereal: Cornflakes, sultana bran, bran flakes, coco pops, puffed wheat, and rice krispies
  • Bread: White bread, bagel, and French baguette
  • Vegetables: Pumpkin and parsnips
  • Fruits: Dates and watermelon
  • Staples: Instant white rice, glutinous rice, short grain white rice, tapioca, mashed potatoes (fresh, instant), and French fries
  • Snacks and Sweet Foods: Pretzels, water crackers, puffed crispbread, donuts, rice cakes, scones, and maple syrup


Breads High in Carbs

Avoid high GI foods like bread as a part of the GI Diet


Advantages of the GI Diet

  • Easy to Follow: Compared to other stricter and regimented diets, the GI Diet is easy to follow and there is no need for special meals as the whole family can eat the same meals. Also, the diet does not involve too much of calorie or carb counting. Foods are marked using the traffic light principle, which is quite easy to understand- green and yellow foods are allowed by the GI Diet and the red light foods are the foods to be avoided. Doesn’t get simpler than that!
  • No Deprivation: There is no major restriction on foods, be it carbohydrates, proteins or fats. Of course, the diet ranks the food according to the glycemic index and categorizes the food as good, not so good and bad, but there’s really no deprivation per se.
  • Diet Good for Health: The GI Diet has many positive aspects and eating low glycemic foods can be beneficial to your health, as we mentioned earlier. This kind of eating keeps your insulin and sugar levels in check and does not restrict consumption of any essential food groups.
  • Risk of diseases: The GI Diet can help to reduce the risk of type-2 diabetes8, prostate cancer9 and stroke10. The GI diet can also help to improve “good” cholesterol levels that help to reduce the risk of heart disease11.
  • Lose Weight: Following the GI Diet can help you lose weight as the foods that you will be eating on the diet keep you satiated for longer periods of time12. However, you must keep a check on the fat content of the foods that you are eating as low GI does not necessarily translate into low-fat.


Disadvantages of the GI Diet

  • Difficult to Identify GI Value of Meal: One of the main drawbacks of the GI Diet is that it is difficult to estimate the GI value of the meal, and just because the GI value of some food is low doesn’t mean it is healthy. For example, some foods with a very low GI value may be packed with fat or salt which may be quite harmful to health. On the contrary, some high glycemic index foods can be quite nutritious.
  • No Advice on Non-Carb Foods: The GI Diet does not offer advice on non-carb foods and it is up to you to figure out how much fat and how many calories you are getting each day. If, like us, you’re someone who has difficulty even figuring out what 2 plus 2 is, you’re going to be climbing your Mt. Olympus!
  • No Portion Control: Since the diet does not specify portion sizes, there is a possibility of overeating even if they are nutritious foods, which can cause weight gain. Too much of a good thing can also be a bad thing, remember?


Woman Eating Healthy Food

Eat as much as you want as long as you’re eating healthy and sticking to the foods allowed on the GI Diet


Common Myths and Misconceptions About the Glycemic Index


You Should Never Eat Foods with High GI Value

“Moderation”. This golden word that applies to most diet and healthy lifestyles is also highly relevant to the GI diet as well. Following any low glycemic diet is all about moderation. When making a choice of food, GI value is only one of the factors to be considered. More importantly, you should consider the total nutrient value of the food such as vitamins, minerals, fiber, antioxidants, carb content, fat content, and sodium content of the food. Quite a lengthy list, we know, so here’s an example to ease it up. Popcorn has a high GI value; however it is made of whole grain and is a good source of fiber. When you want to eat high a GI food, a good idea is to balance it with a lean protein or low GI foods.

High GI Foods Will Make You Gain Weight

Much as it makes life difficult, there are many factors associated with weight gain such as high calorie intake, decreased metabolism, insulin resistance, and other health problems. Some high GI foods are higher in calories, but it is also true that some lower GI foods are also high in calories.

Watermelon Has a High GI and So It Is Bad for You

Watermelon has a high water content which gives it a low energy density. Eating watermelon fills you up and keeps you full and satisfied for a longer period of time. Watermelon is also very good for health as it a wonderful source of vitamin A, C and potassium. While it is true that watermelon has a high GI value of 72, the glycemic load of watermelon is only 4, because the carbohydrate content in watermelon is not much and it has more of water and fiber. What all this scientific talk simply means is that watermelon can be included as part of a healthy meal or snack.


Although watermelon has a high GI value of 72, its GL is just 4 which qualifies it to be consumed as a part of the GI Diet


Potatoes Are Bad for You

Potatoes may have a high GI but that does not mean that potatoes should be eliminated from your diet completely. Potatoes are a good source of vitamins C, B6 and potassium, which makes them a healthy part of your meals. You can include a small portion of baked or boiled potato as part of your meal. Also, cooking potatoes with a little acid such as lemon juice helps to lower the glycemic load.

High GI Foods Cause Type-2 Diabetes

Let’s get this clear. Eating foods with a high GI value or consuming carbohydrates does not cause type-2 diabetes. Type-2 diabetes is the result of genetics and lifestyle factors such as lack of exercise and obesity13. However, if you have been diagnosed with diabetes, then you must be careful about your food consumption and control carb and calorie intake, as consuming large amounts of high GI foods can make it difficult to manage the disease.

You Can Eat as Much of Low GI Foods as You Want and Lose Weight

This fact’s about as true as the fact that Hitler had a Jewish grandfather. Or that “valar morghulis” is High Valyrian for “You know nothing, Jon Snow!”. If you still haven’t figured it out, what we’re trying to tell you is that it’s untrue. You can eat all the low GI foods that you want, but you must keep track of the calories you’re consuming if you want to lose weight. This is because some low GI foods are high in calories. For example, nuts have a GI of less than 30. If you eat at least a handful of nuts, it contains more than 400 calories which can hamper your weight loss efforts.

Low GI Foods Are Always Nutritious

For any food to be considered nutritious, it must be rich in mineral, vitamins, fiber, healthy fats and protein. Many low GI foods are nutritious as they are whole foods such as whole grains, vegetables and fruits. However, some lower GI foods such as candy bars are simply not healthy and are not nutritious. And no, just because they’re still peanuts, though covered in chocolate, doesn’t make them any healthier. 

All High GI Foods Have Little or No Nutritional Value

Again, a fact that’s about as true as Garfield being a dog. Some high GI foods contain plenty of essential vitamins, minerals and even fiber. For example, many whole grains have a medium to high GI value. Whole grain bread has a high GI value but is a great way to increase your fiber intake and a source of vitamin B. Similarly, potatoes are also high GI, but are plant-based food that contains vitamin C and other beneficial nutrients. Sometimes, you must look beyond the GI value of foods and learn to eat nutritious and healthy foods.

Whole Wheat Bread

Whole grain bread, although high in GI value, is rich in many nutrients and fiber


Other Uses

The GI Diet can be beneficial in reducing several diseases such as:

  • Type-2 diabetes
  • Colon and prostate cancer
  • Heart disease
  • Stroke


Phases of the Diet

The GI Diet has two phases:

Phase 1

In the first phase of the diet, you can eat only green light foods. This helps you lose weight as the foods in this category are high in fiber and low in calories. These foods help to fill you up and shed the unwanted pounds.

Phase 2

In Phase 2, the weight loss is maintained by eating green and yellow light foods. In this phase your diet plan includes 55 percent carbs, 25 percent protein and 20 percent fats. It is also recommended that you begin exercising in this phase (Thought you could get away without exercising, did you? Think again!).

Who Is It For?

  • If you are looking to lose weight by following a healthy diet and lifestyle and keep off the pounds for life, then the GI Diet is for you.
  • If you are a person who is extremely active and rely on carbs for extended energy, then the GI diet is suitable for you.
  • The GI Diet can help if you have diabetes as including foods with low GI value can help to maintain blood sugar levels. The diet can also be beneficial if you have prediabetes or you are insulin resistant14.
  • The GI Diet can be followed by pregnant women or nursing mothers too.
  • The GI Diet could be very beneficial for you if you have a combination of high blood pressure, cholesterol, heart disease and if you are overweight.
  • If you are a vegetarian, have to follow a gluten-free diet, or have any other dietary restrictions, then you can easily follow the GI Diet. You can choose from a variety of foods from the recommended food list but you may need to replace foods such as whole wheat pasta instead of consuming white pasta or whole grain bread instead of white bread.  



Replace white pasta with whole wheat pasta


Who Is It Not For?

The GI Diet can be followed by almost everyone as it advocates healthy eating and does not eliminate any food groups. However, if you are suffering from diabetes or any other ailments for which you are under medication, then it is recommended that you consult with your doctor before starting the diet.

The Final Word

The GI Diet is not only popular but is probably the answer to healthy dieting as it recommends eating as per the healthy eating guidelines. Developed as a means to treat people with diabetes to manage their sugar level, the GI diet has become a way to healthy eating, overall health and also weight loss. The diet plan recommends eating plenty of vegetables and fruits and eliminates sugary and processed carbs. Selecting foods on basis of their glycemic index can help you lose those pounds as many foods in a low-fat, well-balanced and healthy diet including whole grains, vegetables, fruits and low-fat dairy products have low GI values. However, one minus is that the diet does not recommend the number of calories you must consume, so it is up to you to decide what the appropriate calorie intake is for you. While you will definitely be healthier when on the GI Diet, you may not shed the weight that you want to if you do not keep track of your calorie consumption. Following the GI Diet isn’t a temporary solution to weight loss. Rather it is a lifestyle change to maintain good health and keep off the weight permanently. So take charge of your health, eat healthy, exercise regularly and stay fit! Remember, your focus determines your reality. May the Force be with you!