The Shopper's Guide to GI Values

Understanding the GI

Using the Shopper’s Guide

We have put together this handy guide full of GI values to help you put those low GI smart carb food choices into your shopping cart and on your plate. By doing so, you’ll satisfy your hunger, increase your energy levels, and eliminate your desire to eat more than you should.

Some foods that have been tested by accredited laboratories display the certified GI symbol. But what about the rest? With tables listing the GI of hundreds of foods—from breads and breakfast bars to fruit juice, fruit, and vegetables—this book will save you time in the supermarket by directing you to the best low GI foods available.

You can use the GI tables on pages 98–247 to:

  find the GI of your favorite foods

  compare foods within a category (two types of bread, for example)

  improve your diet by finding a low GI substitute for high GI foods

  put together a low GI meal

  shop for low GI foods including gluten-free options

Low GI eating

Making the change

Eating the low GI way simply involves replacing high GI foods in your diet with low GI foods. This could mean eating muesli at breakfast instead of wheat flakes, low GI bread instead of normal white or whole wheat bread, or a sparkling apple juice in place of a soft drink.

You don’t need to count numbers or do any sort of mental arithmetic to make sure you are eating a healthy low GI diet.

Tips for putting the GI into practice

Be aware! Only carbohydrate-containing foods have GI values

The diet we eat contains three main nutrients: protein, carbohydrate, and fat. Some foods, such as meat, are high in protein, while bread is high in carbohydrate and butter is high in fat. We need to consume a variety of foods (in varying proportions) to provide all three nutrients, but the GI applies only to carbohydrate-rich foods. It is impossible for us to measure a GI value for foods like meat that contain negligible carbohydrate. The same applies to cheese, eggs, avocado, butter, oil, and alcohol. It is incorrect to refer to these foods as high or low GI. There are other nutritional aspects that you could consider in choosing these foods: for example, the amount and type of fats they contain.

The GI is not intended to stand alone

We don’t categorize foods as “good” or “bad” according to their GI. While you will benefit from eating low GI foods at each meal, this doesn’t have to be at the exclusion of all others. High GI foods like most potatoes and bread still make valuable nutritional contributions to our diet. And low GI foods like pastry that are high in saturated fat are no better for us because of their low GI. The nutritional benefits of different foods are many and varied, and it is advisable for you to base your food choices on the overall nutritional content of a food, particularly considering the saturated fat, salt, and fiber in addition to GI.

You don’t need to add up the GI each day

Although we can predict the GI of a menu for the whole day, we can’t predict the GI of many recipes, especially those using flour. That’s why we now prefer simply to categorize foods as low, medium, or high GI in most circumstances. We have also found that many people who substitute low for high GI foods in their everyday meals and snacks reduce the overall GI of their diet, gain better blood glucose control, and lose weight.

You don’t need to be pedantic about GI values

Whether a food’s GI is 59 or 61 isn’t biologically relevant. Normal day-to-day variation in the human body could obscure the difference in these values. Generally, a variation of more than 5 could be considered different.

This for that—substituting high GI with low GI foods

Simply substituting high GI foods with low GI alternatives will give your overall diet a lower GI and deliver the benefits of low GI eating. Here’s how you can put slow carbs to work in your day by cutting back consumption of high GI foods and replacing them with alternatives that are just as tasty.

Your GI Q&A

Does low carb automatically mean low GI?

Not at all. Low carb is just about quantity; it simply means that a food or meal does not contain much carbohydrate at all. It says nothing about the quality of the carbs in the food or meal on your plate. You could be eating a low carb meal, but the carbs have a medium or high GI. Low GI, on the other hand, is all about quality. Whether you are a moderate or high carb eater, low GI carbs (whole grain breads, legumes/beans, many fruits and vegetables) will have significant health benefits—promoting weight control, reducing your blood glucose and insulin levels throughout the day, and increasing your sense of feeling full and satisfied after eating. We suggest that you make the most of quality carbs and reap the add-on health benefits such as:

  Vitamin E from whole grain cereals

  Vitamin C, beta-carotene, and potassium from fruits and vegetables

  Vitamin B6 from bananas and whole grain cereals

  Pantothenic acid, zinc, iron, and magnesium from whole grains and legumes

  Antioxidants and phytochemicals from all plant foods

  Fiber, which comes from all of the above and doesn’t come from any animal food

Why do many high-fiber foods have a high GI value?

Dietary fiber is not one chemical constituent like fat and protein. It is composed of many different sorts of molecules and can be divided into soluble and insoluble types. Soluble fiber is often viscous (thick and jelly-like) in solution and remains viscous even in the small intestine. For this reason it makes it harder for enzymes to move around and digest the food. Foods with more-soluble fiber, like apples, oats, and beans, therefore have low GI values.

Insoluble fiber, on the other hand, is not viscous and doesn’t slow digestion unless it’s acting like a fence to inhibit access by enzymes (e.g., the bran around intact kernels). When insoluble fiber is finely milled, the enzymes have free reign, allowing rapid digestion. Whole wheat bread and white bread have similar GI values. Brown pasta and brown rice have similar values to their white counterparts.

Should I avoid all high GI foods?

There is no need to eat only low GI foods. While you will benefit from eating low GI foods at each meal, this doesn’t have to be to the exclusion of all others. When eaten with protein foods or low GI foods, the overall GI value of the meal will be about medium.

What GI number should a person aim for when trying to diet?

The simple answer is there’s no formula. You don’t need to add up the GI each day. In fact there’s no counting at all as there is with calories. The basic technique for eating the low GI way is simply switching the high GI carbs in your diet with low GI foods. So, what you need to aim for is identifying the high GI carbs in your current diet and swapping them for some quality low GI carbs. When you’re looking at GI values, it’s best to compare like with like, one bread with another, for example, rather than “bread” with “fruit.” This way you’ll be comparing foods of similar nutritional value which will help you to make an appropriate swap from the high GI to the low GI version. Try keeping these simple guidelines in mind: