Glycemic Index

We have already sorted out the main food components and their caloric content, but there is one more important parameter – the glycemic index. What is it and why is it should be taken into account when selecting foods and planning diet, especially being at the weight loss stage?

The glycemic index (GI) is the rate at which carbohydrates contained in food are absorbed in in the body and, accordingly, increase the sugar level in blood. The food glycemic index is the measure of the speed at which glucose is released into the blood stream after it’s digested.

A whole grain like brown rice or quinoa will result in a slower release of glucose and a more muted insulin response. On the other hand, a food that’s high in refined carbohydrates, like white bread or soda, will lead to a more rapid release of glucose into the blood. And in response to this, the body releases a large amount of insulin, the hormone in our bodies that lowers blood sugar. Because of spike of glucose and insulin lead to less stable blood sugar levels, eating foods that are refined, especially highly processed carbohydrates, can result in an earlier return of hunger and a tendency to overeat. The glycemic index of a food is lower when the food contains fiber or when it’s eaten in combination with protein foods or foods containing some dietary fat.

The glycemic index can be low (55 and below), average (56-60) and high (70 and more).

All foods can also be divided into three categories: with high GI, medium GI and low GI.

It is possible to determine which category a particular food belongs to using special tables in which the food GI is already calculated. You can find them in search engines, for example, in Google.  Also you can use this simplified format:

Glycemic index and satiety

When sugar content in blood rises, human feels satiety. A decrease in sugar content in blood is accompanied by a feeling of hunger. The higher the sugar content rise in the blood, the faster it is also decrease. That is, a high jump is followed by the same high drop.

Our goal is to get continuous satiety from food! Therefore, the optimal foods for composing a diet are foods with low and medium GI.  Satiety after their use comes more slowly, but also smoothly and goes away, which makes us feel full for a longer time.

But choosing foods with a high GI, you can quickly to satisfy the feeling of hunger, but, unfortunately, it will come back again soon. That is, prolonged saturation by foods with high GI is not given.  Therefore, this food category should be excluded from the diet during the weight loss period, and in everyday nutrition use them occasionally and mainly as dessert, that is, to eat at the end of a meal.

For people who are struggling to manage their weight, or their blood sugar levels, eating foods that have a low glycemic index is especially important, but choosing low glycemic foods is generally a good idea for all us. So when we talk about dietary carbohydrates we’re actually talking about a very broad family of foods. Some that can be harmful to our long term health, and some that can support it. Learning how to choose the right foods within each nutrient category is one of the keys to long term success.

Glycemic Index Food Guide

The glycemic index (GI) is a scale that ranks a carbohydrate-containing food or drink by how much it raises blood sugar levels after it is eaten or drank. Foods with a high GI increase blood sugar higher and faster than foods with a low GI.

There are three GI categories:
Green = Go
Low GI (55 or less) Choose Most Often
Yellow = Caution
Medium GI (56 to 69) Choose Less Often
Red = Stop and think
High GI (70 or more) Choose Least Often
Foods in the high GI category can be swapped with foods in the medium and/or low GI category to lower GI.
A low GI diet may help you:
• decrease risk of type 2 diabetes and its complications
• decrease risk of heart disease and stroke
• feel full longer
• maintain or lose weight
Try these meal planning ideas to lower meal GI:
• Cook your pasta al dente (fi rm). Check your pasta package instructions for cooking time.
• Make fruits and milk part of your meal plate (Figure 1). These foods often have a low GI and make a healthy dessert.
• Try lower GI grains, such as barley and bulgur.
• Pulses can be grains and starches or meat and alternatives. Swap half of your higher GI starch food serving with beans, lentils or chickpeas. For example, instead of having 1 cup of cooked short grain rice, have ½ cup of cooked rice mixed with ½ cup of black beans.

Diabetes Canada recommends choosing lower GI foods and drinks more often to help control blood sugar.
Work with your Registered Dietitian to add foods and drinks to your lists, create action plans that include choosing lower GI foods, adapt your favourite recipes, and find ways to swap/substitute low GI foods into your meal plan.
Checking your blood sugar before, and 2 hours after, a meal is the best way to know how your body handles certain foods and drinks.

Figure 1: The Plate Method. Using a standard dinner plate, follow this model to control your portion sizes.
www.diabetes.ca/mealplanning

Some carbohydrate-containing foods and drinks have so little carbohydrate that they do not have a GI value. This does not mean they cannot be included as part of a healthy diet. Examples include green vegetables, lemons, and some lowcarbohydrate drinks. Diabetes Canada calls these foods and drinks “free” because they do not impact the blood sugar of people living with diabetes. You can put free foods in the green category, but they do not have a GI and have not been included in the food lists

Grains and Starches

* Most starchy/sweet vegetables (e.g. peas, parsnip, winter squash) provide 15 g or more carbohydrate per 1 cup serving. Beets and carrots often provide less than 15 g carbohydrate per serving (marked above with *). Most non-starchy (or free) vegetables (e.g. tomato and lettuce) have not been assigned a GI because they have very little carbohydrate and have very little effect on blood sugar.

Fruits

Some fruits have not been assigned a GI because they contain less than 15 g of available carbohydrate per serving (e.g. lemon and lime).

Many fruits and vegetables fall in the low or medium GI categories.

Meat and Alternatives

Meat, poultry and fi sh do not have a GI because they do not contain carbohydrate. When ½ cup or more of pulses are eaten, they can be included in the Grains and Starches food group or the Meats and Alternatives group.