The Glycemic Index

The Glycemic Index is a number that represents how quickly after a food is eaten that it affects your body in the form of an insulin reaction. Foods that have a high glycemic index trigger an undesirable insulin response, which is an insulin spike (insulin level is high). This means that there is an excess amount of insulin in the bloodstream and this promotes fat storage. Just the opposite, foods that are low on the glycemic index do not elevate insulin levels. Low glycemic products as said to reduce excess fat storage, increase and sustain energy levels and increase mental alertness. A high level of insulin is followed by a very low level of insulin, called a 'crash'. This is when you feel tired and may even think you're hungry because your body is trying to raise insulin levels back to normal levels. Most of the glycemic charts we've seen have ranked carbohydrates from 0 - 100. Simple sugars, that cause an undesirable insulin spike, are higher in number. Examples of foods with a high glycemic index are flour and sugar. Think of all the foods that have either of these ingredients: bread, doughnuts, jelly beans, cookies, bananas... the list goes on and on. Examples of foods with lower glycemic indexes include more complex carbs: yams, beans, oatmeal and broccoli. These are better food choices because they will not release insulin into your system anywhere near as quickly. An important note is that just because a product is low in carbohydrates does NOT mean it has a low glycemic index. The type of carbohydrates and their relationship to the other ingredients in the product as well as processing dictates a low glycemic index rating and how they affect the human body. The only way to determine a glycemic rating for any product is to subject it to specific analytical testing. What is Glycemic Index? Generally it is assumed that simple carbohydrates increase blood glucose levels rapidly, and complex carbohydrates have a slower effect. However, recent work into the Glycemic Index (GI) and Glycemic Load (GL) has changed the understanding of the relationship between ingested carbohydrates and blood glucose levels. The glycemic index (GI) is a measure of how fast a carbohydrate triggers to raise the blood sugar. Some carbohydrates are slow releasing, while the others are fast releasing. The higher the number, the greater the blood sugar response. All carbohydrates can be assigned a value, known as glycemic index, compared to glucose. The glucose is the fastest releasing carbohydrate so it has been assigned a glycemic value of 100. Based on glycemic index values, Maltodextri, a glucose polymer is a complex carbohydrate, but it has a GI of ~100 . This means that it rapidly raises blood glucose levels. Fructose, a simple carbohydrate has GI of ~20. The glycemic index is a better method for classifying good and bad carbohydrates as it relies upon actual post-meal blood glucose response A low glycemic index value for a food indicates a slow rise in blood glucose and insulin levels. Conversely, a high GI value indicates that it results in a rapid rise in blood glucose levels and hence a spike in insulin response. What is Glycemic Load? A glycemic index value tells you only how rapidly a particular carbohydrate turns into sugar. It doesn't tell how much of that carbohydrate is in a serving of a particular food. Both the things are important to understand a food’s effect on blood sugar. The glycemic index value alone does not give accurate picture of the food. The glycemic load (GL) takes both the things into account.

The glycemic load is the glycemic index divided by 100 multiplied by its available carbohydrate content (i.e. carbohydrates minus fiber) in grams. The following table lists GI and GL values of certain foods. (The “Serve size (g)” column is the serving size in grams for calculating the glycemic load.). _____________________________________________ Value Glycemic Index(GI) Glycemic Load(GL) _____________________________________________ High 70 or more 20 Medium 56 to 69 inclusive 11 to 19 inclusive Low 55 or less 10 or less _____________________________________________ Values are with reference to Glucose. Take watermelon as an example of calculating glycemic load. The glycemic index = 72 In a serving of 120 grams, it has 6 grams of available carbohydrate. The glycemic load = (72/100) x 6 = 4.32 = 4 rounded. By simply looking at the glycemic index value you will think that watermelon is not good for you, but its glycemic load is low, so it is safe to eat. Foods that have a low glycemic index invariably have a low GL, while foods with an intermediate or high glycemic index range from very low to very high GL. Therefore, you can reduce the GL of your diet by limiting foods that have both a high glycemic index and a high carbohydrate content. To optimize insulin levels, you should eat fruits, vegetables, and whole grains preferably with low glycemic index and low GL values. The fiber contained in these foods slows down the release of sugars.

The following glycemic index table gives glycemic index food list and glycemic load food list. You can select low glycemic index foods from this list to make your own low glycemic index diet.

Glycemic Index Food List (GI) & Glycemic Load Food List(GL) ______________________________________________ FRUIT AND FRUIT PRODUCTS Item Size Apples Apple juice,unsweetened Apricots Apricots, in syrup Apricots Banana, ripe Banana, under-ripe Banana, over-ripe Cherries Cranberry juice Custard apple Dates, dried Figs, dried

GI

Serve

GL

38 40 57 64 31 51 30 48 22 68 54 103 61

120 250 120 120 60 120 120 120 120 250 120 60 60

6 11 5 12 9 13 6 12 3 24 10 42 16

Grapefruit 25 120 Grapefruit juice, 48 250 unsweetened Grapes 46 120 Grapes, black 59 120 Kiwi fruit 53 120 Lychee, canned in syrup 79 120 Mango 51 120 Marmalade orange 48 30 Oranges, 42 120 Orange juice 52 250 Paw paw/papaya 59 120 Peach 42 120 Peach, in natural juice 38 120 Peach, in heavy syrup 58 120 Pear 38 120 Pear halves, in syrup 25 120 Pineapple 59 120 Plum 39 120 Prunes, pitted 29 60 Raisins 64 60 Rock melon/Cantaloupe 65 120 Strawberries, fresh 40 120 Strawberry jam 51 30 Sultanas 56 60 Tomato juice, 38 250 no added sugar Watermelon 72 120 _____________________________________________ VEGETABLES

3 9

Item GI Serve Size Broad beans 79 80 Green peas 48 80 Pumpkin 75 80 Sweet corn 54 80 Beet root 64 80 Carrots 47 80 Cassava, boiled 46 100 Parsnips 97 80 Baked potato 85 150 Desiree potato, boiled 101 150 White potato, cooked 50 150 French fries, frozen, 75 150 reheated Instant Mashed potato 85 150 New Potato 57 150 Sweet potato 61 150 _____________________________________________

GL

8 11 6 16 8 9 5 12 10 5 4 9 4 4 7 5 10 28 4 1 10 25 4 4

9 3 3 9 5 3 12 12 26 17 14 22 17 12 17

LEGUMES AND NUTS Black-eye beans, boiled 42 150 Butter beans, cooked 31 150 Chana dal, dry, 5.3 50 Chickpeas (Bengal gram), 28 150 boiled Haricot/Navy beans 38 150 Kidney Beans, boiled 28 150 Black bean, cooked 20 150 Lentils, green, boiled 30 150 Lentils, red, dried, 26 150 Lima beans, frozen, 32 150 reheated in microwave oven Marrow fat peas, boiled 39 150 Mung bean, cooked 42 150 Peas, dried, boiled 22 150 Pigeon Pea soaked, 22 150 boiled Pinto beans, dried, 39 150 Romano beans 46 150 Soya beans, boiled 15 150 Split peas, boiled 32 150 _____________________________________________ OTHER ITEMS

13 6 1 8

Coca Cola Smoothie, raspberry Happiness™ bread Muesli bread Wonder white bread All-Bran (Kellogg's) Corn flakes Raisin Bran (Kellogg's) Rice, boiled white Rice, boiled Long grain Jasmine rice, Basmati rice, boiled Brown, steamed Semolina, roasted

16 14 9 7 10 9 21 12 23 23 46 22 16 6

63 33 63 54 73 38 81 61 64 56 109 58 50 55

250 250 30 30 30 30 30 30 150 150 150 150 150 150

Going with the (Whole) Grain We've come a long way from the days when one of the knee-jerk answers to the question "What should I eat?" was "Get a lot of carbohydrates." We now know that the staple of most diets, carbohydrates, aren't all good or all bad. Some kinds promote

12 7 5 5 5 10 7 7 2 4 10 8 1 6

health while others, when eaten often and in large quantities, actually increase the risk for diabetes and coronary heart disease. The resurgence of the Atkins diet and the rise of the South Beach and other lowcarbohydrate diets have put the focus on the carbohydrates. While it may be true that easily digested carbohydrates from white bread, white rice, pastries, and other highly processed foods may contribute to weight gain and interfere with weight loss, that doesn't mean all carbohydrates are suspect. Regardless of what you've read or heard about the dangers of carbohydrates, they are an important part of a healthy diet. Carbohydrates provide the body with the fuel it needs for physical activity and for proper organ function. The best sources of carbohydrates - fruits, vegetables, and whole grains - deliver essential vitamins and minerals, fiber, and a host of important phytonutrients. What are Carbohydrates? Carbohydrates come from a wide array of foods - bread, beans, milk, popcorn, potatoes, cookies, spaghetti, corn, and cherry pie. They also come in a variety of forms. The most common and abundant are sugars, fibers, and starches. The basic building block of a carbohydrate is a sugar molecule, a simple union of carbon, hydrogen, and oxygen. Starches and fibers are essentially chains of sugar molecules. Some contains hundreds of sugars. Some chains are straight, others branch wildly. Carbohydrates were once grouped into two main categories. Simple carbohydrates included sugars such as fruit sugar (fructose), corn or grape sugar (dextrose or glucose), and table sugar (sucrose). Complex carbohydrates included everything made of three or more linked sugars. Simple sugars were considered bad and complex carbohydrates good. The picture is much more complicated than that. The digestive system handles all carbohydrates in much the same way - it breaks them down (or tries to break them down) into single sugar molecules, since only these are small enough to cross into the bloodstream. It also converts most digestible carbohydrates into glucose (also known as blood sugar), because cells are designed to use this as a universal energy source. Fiber is an exception. It is put together in such a way that it can't be broken down into sugar molecules, and so passes through the body undigested. Carbohydrates and the Glycemic Index A new system for classifying carbohydrates calls into question many of the old assumptions about how carbohydrates affect health. This new system, known as the glycemic index, measures how fast and how far blood sugar rises after you eat a food that contains carbohydrates. (1). White bread, for example, is converted almost immediately to blood sugar, causing it to spike rapidly. It's classified as having a high glycemic index. Brown rice, in contrast, is

digested more slowly, causing a lower and more gentle change in blood sugar. It has a low glycemic index. The most comprehensive list of the glycemic index of foods was published in the July, 2002, issue of the American Journal of Clinical Nutrition (2). A searchable database maintained by the University of Sydney is available online. Diets filled with high-glycemic-index foods, which cause quick and strong increases in blood sugar levels, have been linked to an increased risk for both diabetes (3, 4) and heart disease. (5, 6) On the other hand, lower GI foods have been shown to help control type 2 diabetes. (7) One of the most important factors that determine a food's glycemic index is how highly processed its carbohydrates are. Processing carbohydrates removes the fiber-rich outer bran and the vitamin- and mineral-rich inner germ, leaving mostly the starchy endosperm. (See Fiber for more information on whole-grain foods.) Other factors that influence how quickly the carbohydrates in food raise blood sugar include: •

• •

• •

Fiber content. Fiber shields the starchy carbohydrates in food immediate and rapid attack by digestive enzymes. This slows the release of sugar molecules into the bloodstream. Ripeness. Ripe fruits and vegetables tend to have more sugar than unripe ones, and so tend to have a higher glycemic index. Type of starch. Starch comes in many different configurations. Some are easier to break into sugar molecules than others. The starch in potatoes, for example, is digested and absorbed into the bloodstream relatively quickly. Fat content and acid content. The more fat or acid a food contains, the slower its carbohydrates are converted to sugar and absorbed into the bloodstream. Physical form. Finely ground grain is more rapidly digested, and so has a higher glycemic index, than more coarsely ground grain.

All these elements lead to sometimes counterintuitive results. Some foods that contain complex carbohydrates, such as potatoes, quickly raise blood sugar levels, while some foods that contain simple carbohydrates, such as whole fruit, raise blood sugar levels more slowly. There is one thing that a food's glycemic index does not tell us: the relative amount of carbohydrate in a given food. Take watermelon as an example; the sweet-tasting fruit has a high glycemic index. But a slice of watermelon has only a small amount of carbohydrate per serving (as the name suggests, watermelon is made up mostly of water). Looking at the glycemic index alone may not tell us everything we need to know about a food's impact on blood sugar levels. So researchers have developed a new way of classifying foods that takes into account both the amount of carbohydrate in the food and

the impact of that carbohydrate on blood sugar levels. This measure is called the glycemic load. (8, 9) A food's glycemic load is determined by multiplying its glycemic index by the amount of carbohydrate it contains. (For a listing of low, medium and high glycemic load foods, see the sidebar, Carbohydrates and the Glycemic Load.) Although the fine points of the glycemic index and glycemic load may seem complicated, the basic message is simple: Whenever possible, replace highly processed grains, cereals, and sugars with minimally processed whole-grain products. And only eat potatoes - once on the list of preferred complex carbohydrates - occasionally because of their high glycemic index and glycemic load. When Sugar Management Goes Awry Digestible carbohydrates are broken down in the intestine into their simplest form, sugar, which then enters the blood. As blood sugar levels rise, special cells in the pancreas churn out more and more insulin, a hormone that signals cells to absorb blood sugar for energy or storage. As cells sponge up blood sugar, its levels in the bloodstream fall back to a preset minimum. So do insulin levels. In some people, this cycle doesn't work properly. People with type 1 diabetes (once called insulin-dependent or juvenile diabetes) don't make enough insulin, so their cells can't absorb sugar. People with type 2 diabetes (once called non-insulin dependent or adult onset diabetes) usually start out with a different problem - their cells don't respond well to insulin's "open up for sugar" signal. This condition, known as insulin resistance, causes both blood sugar and insulin levels to stay high long after eating. Over time, the heavy demands made on the insulin-making cells wears them out, and insulin production slows, then stops. Insulin resistance isn't just a blood sugar problem. It has also been linked with a variety of other problems, including high blood pressure, high levels of triglycerides, low HDL (good) cholesterol, heart disease, and possibly some cancers. (10) Genes, a sedentary lifestyle, being overweight, and eating a diet filled with foods that cause big spikes in blood sugar can all promote insulin resistance. Data from the Insulin Resistance Atherosclerosis Study suggests that cutting back on refined grains and eating more whole grains in their place can improve insulin sensitivity. (11) No Carbohydrates? Some popular diets, particularly the Atkins diet, treat carbohydrates as if they are evil, the root of all body fat and excess weight. While there is some evidence that a lowcarbohydrate diet may help people lose weight more quickly than a low-fat diet (12, 13), no one knows the long-term effects of eating little or no carbohydrates. Equally worrisome is the inclusion of unhealthy fats in some of these diets.

If you want to go the lower carb route, try to include some fruits, vegetables, and wholegrain carbohydrates every day. They contain a host of vitamins, minerals, and other phytonutrients that are essential for good health and that you can't get out of a supplement bottle. Adding Good Carbohydrates Carbohydrates from fruits, vegetables, and grains should give you the bulk of your calories. For optimal health, get your grains intact from foods such as whole wheat bread, brown rice, whole-grain pasta, and other possibly unfamiliar grains like quinoa, whole oats, and bulgur. Not only will these foods help protect you against a range of chronic diseases, they can also please your palate and your eyes. Until recently, you could only get whole-grain products in organic or non-traditional stores. Today they are popping up in more and more mainstream grocery stores. Here are some suggestions for adding more whole grains to your diet: •

• • •

Start the day with whole grains. If you're partial to hot cereals, try old-fashioned or steel-cut oats. If you're a cold cereal person, look for one that lists whole wheat, oats, barley, or other grain first on the ingredient list. Use whole-grain breads for lunch or snacks. Check the label to make sure that whole wheat or other whole grain is the first ingredient listed. Bag the potatoes. Instead, try brown rice or even "newer" grains like bulgur, wheat berries, millet, or hulled barley with your dinner. Pick up some whole wheat pasta. If the whole-grain products are too chewy for you, look for those that are made with half whole-wheat flour and half white flour.