Glycemic Index

Understanding Carbohydrates:

When it comes to carbohydrates, they are commonly broken down on a nutritional panel into complex carbohydrates, simple sugars, and fiber.

Fiber: Fiber can be either soluble or insoluble. This simply tells us whether it absorbs water or dissolves in water. Usually fiber in a food is actually a combination of soluble and insoluble fiber; however, certain plants are predominantly one or the other. Most fiber from vegetables, fruits, and grains, including wheat and oat bran as well as flax, are primarily made of soluble fiber. Fibers from coconuts are almost solely insoluble. Fiber often takes time to break down and fiber content is not digestible by humans. Some of this fiber we eat is digested by friendly bacteria living in the intestinal tract. This gives us good by-products that benefit us. The fiber that is never digested helps with elimination and movement through the bowels keeping them clean and healthy. All fiber is considered healthy, whether soluble or insoluble, digestible or non-digestible.

Starch and other Complex Carbohydrates. These types of carbohydrates are simply large molecules made of many simple sugars. Starch and other complex carbohydrates are relatively easy for us to digest and their digestion begins early (in the mouth). All carbohydrates eventually break down into simple sugars. These sugars are Glucose, Galactose, Maltose, Lactose, Dextrose, and Fructose. These sugars can, also, be found in our foods in their simple form. They give flavor and sweetness to our foods. The body converts these simple sugars into glucose, the only sugar that enters the blood stream. Glucose is the carbohydrate found in body tissues and cells with the exception of glycogen. Glycogen is simply glucose molecules linked together for storage in the liver. Any glucose that enters the bloodstream which is not needed immediately for energy is merely converted into triglycerides and put into fat storage.

When carbohydrates are broken down during digestion, the rate at which they enter the blood stream as glucose varies depending on the ease of digestion and conversion to glucose, other foods eaten with the carbohydrate food, and other components of that food. Terms such as complex carbohydrates, fiber and sugars, which people look at to discern “healthier” foods from less healthy foods, commonly appear on food labels. As you will see in the chart below, they are not the most accurate way of assessing the available sugars and the blood sugar response in the body. Some in the nutrition world do not currently recognize these nutrition facts as having nutritional or physiological significance. Some, such as the WHO/FAO, have recommended that these terms be removed and replaced with the total carbohydrate content of the food and its GI value.

What is the Glycemic Index?

The glycemic index (GI) is a ranking of carbohydrates on a scale from 0 to 100 according to the extent to which they raise blood sugar levels (glucose levels) after eating. Foods with a high GI are those which are rapidly digested and absorbed causing large fluctuations in blood sugar levels. Low-GI foods, by virtue of their slow digestion and absorption, produce gradual rises in blood sugar and insulin levels. Low GI diets have been shown to improve both glucose and lipid levels in people with blood sugar problems. They have benefits for weight control because they help control appetite and delay hunger. Low GI diets also support normal insulin levels and a reduction in insulin resistance.

How the Glycemic Index is measured:

There are two reputable universities where testing for the glycemic index of foods is done. One is in Sydney Australia ( The Human Nutrition Unit at the University of Sydney)http://www.glycemicindex.com/ and the other in Ontario, Canada ( University of Toronto 's Department of Nutritional Sciences) http://www.news.utoronto.ca/bin6/060623-2395.asp. To determine a food's GI rating, the food (usually 50 grams of carbohydrate) is fed to 10 healthy people after an overnight fast. Finger-prick blood samples are taken at 15, 30, 45, 60, 90 and 120 minutes after starting to eat . These blood samples are used to construct a blood sugar response curve for that two hour period. The area under the curve (AUC) is calculated to reflect the total rise in blood glucose levels after eating the test food. The GI rating (%) is calculated using pure glucose as the standard .

Since glucose is considered the easiest of all sugars for the body to digest, it is given an arbitrary value of 100 and other carbohydrates are given a number relative to glucose. Carbohydrates that are converted to blood sugar quicker receive higher numbers and will quickly raise low blood sugars. These foods might be best for people experiencing brief periods of intense exercise, but there can be unfavorable effects on health if high glycemic foods are continuously eaten as a common part of the diet. Carbohydrates that are digested and converted into blood glucose at a lower rate will have lower numbers and are helpful for preventing overnight drops in the blood sugar with large fluctuations in blood sugar insulin levels. These types of food are actually best eaten for long periods of exercise and normal daily activities. The average of the GI ratings from all ten of the subjects is published as the GI of that food.

The impact a food will have on the blood sugar depends on many other factors such as ripeness, cooking time, fiber and/or fat content, time of day, blood insulin levels of the individuals, and their recent activity. The more fiber, protein or fat a food contains, the lower the glycemic index. These nutrients slow down digestion and slow down the rate at which glucose enters the blood stream.

Lower percentages of carbohydrates in foods lowers the glycemic index. Foods such as beef, chicken, fish, tofu, eggs, nuts, seeds, avocadoes, many fruits (including berries) and vegetables, wine, beer, and spirits, do not have a glycemic index because they are too low in carbohydrates to affect the blood sugar.

The use of the Glycemic Index is just one of the many tools we have available to help us improve our health and allow us to more accurately assess the effect various foods have on our body.

Applying this information to our diet:

There are many nutritional counselors and oodles of diet programs with instructors who teach people to eliminate carbohydrates from their diet. Their students often times end up with constipation or other bowel problems. They are missing a whole, very important food group that contains powerful antioxidants and enzymes, as well as, very important vitamins and minerals. On the other hand, there are diabetic counselors who encourage whole grains, hot and cold cereal, potatoes, and other foods as healthy. They have very high glycemic indexes. In addition, they may be eliminating important nutrient dense foods that have a low glycemic index.

While most of the energy needed by the body can come from fats and proteins, the brain requires glucose for proper functioning. A diet virtually carbohydrate free affects a persons’ mental capacities. People experience this during extended water fasts longer than 3 or 4 days. The effects of low blood sugar levels in the brain are extremely apparent in water fasts that extend over 14 days. The effects of high blood sugars are equally as damaging. Knowing the glycemic index helps us to make wiser choices.

Foods and their Glycemic Index:

Low glycemic foods are considered to be foods with a GI (glycemic index) of less than 55. Higher GI numbers lead to higher the blood sugar and insulin response to the food.

Focusing on low glycemic foods can be a tool for people watching blood sugar levels to improve their health. I have compiled some glycemic index values for you in a table below:

Please note

Foods with high protein and/or fat content and low carbohydrate content do not exhibit a blood sugar response. Examples of these types of foods are beef, chicken, fish, tofu, eggs, nuts, seeds, and avocadoes.

There are also no glycemic scores for fermented foods where the carbohydrates have been used up during fermentation. These products include such things as wine, beer, and spirits, as well as, unsweetened yogurt, kefir, raw cultured vegetables, and kombucha.

In addition, most vegetables do not exhibit a glycemic response and therefore have no readable Glycemic Index. These vegetables include artichoke, asparagus, Broccoli, cauliflower, celery, cucumber, eggplant, green beans, lettuces of all varieties, peppers, snow peas, spinach, summer squash, tomatoes, and zucchini.

 

A FEW THOUGHTS:

The glycemic index of white bread is 70, yet when eaten with yogurt and a pickle the glycemic index falls to 39 making this a low glycemic “meal.” The GI of yogurt is 23 and it contains probiotic cultures that aid in digestion to help maintain a healthy digestive tract. This same tactic can be used when making a fruit salad. Simply cut up fruit and place it in a bowl with yogurt or on top of yogurt. In this way you do not have to worry about the glycemic response of the sugars, even in a high glycemic fruit blend. In addition, if you add a small amount of a high glycemic food to a meal that is mostly made of low glycemic foods, you will not see the blood sugar response you see when eating that food by itself.

Full fat dairy products (including ice cream) have a low glycemic index. When they are cultured, their glycemic index is even lower. Provided the person has a healthy digestive tract that contains good bacteria, neither digestion should not be a problem nor should allergies. Raw dairy from grass fed cows is loaded with nutrients, essential fatty acids, and enzymes. It should not be considered an unhealthy food by Americans.

Sweet potatoes are actually a tuber formed by a plant from the morning glory family. These tubers are loaded with nutrients and have a lower glycemic index than either rice or white potatoes. Both rice and white potatoes have become the main stay of many “healthy” diets because they tend to fill up the stomach and are gluten free. However, these food sources have very high glycemic indexes. If used they must be accompanied by foods containing fats and proteins such as cheese, sour cream, milk and butter for the potato along with a meat or protein dish. The rice dishes should have nuts, nut butters, milk or other dairy, avocadoes, legume or some other protein with them as well.

Most desserts, candies, and treats have very high glycemic responses in the body. Grains, too, tend to raise blood sugars quickly. However, most fruits and vegetables, as well as dairy and meats have very low glycemic responses. Fruits, especially if accompanied by fermented foods, can be used for delicious desserts so that “treats” can easily be eliminated from the diet. In addition, whole grain products tend to have slightly lower glycemic responses in the body. Unrefined grain products can occasionally be used as a compliment to a meal, but they should never be a foundational part of the meal. This means a breakfast consisting of cereal with milk, donuts, or waffles should be replaced by fresh fruit and yogurt, egg nog, a protein/fruit smoothie, cooked eggs, fermented foods (cultured veggies or cultured dairy), fresh vegetable, or fruit juice with the possibility of a bagel or slice of toast made from whole grains as a complement only.

Sports drinks have very high glycemic indexes, contain food colors and other non-natural artificial chemicals, and are acidifying to the body. Herbal teas, fresh juices, smoothies, and bottled fruit juices are a much better choice for refreshment and replacing electrolytes. Fresh alkaline water, herbal tea sweetened with agave or stevia, and Coconut water is far superior to a sports drink.

Some vegetables like pumpkin and parsnips appear to have a high GI; however , unlike potatoes, grains, and cereals, these vegetables are very low in carbohydrate. So, even though they have a high GI, their glycemic load (GI x carb per serve divided by 100) is low. All vegetable, with the exception of white and red potatoes, contain only small amounts of carbohydrate in conjunction with many micronutrients and should be considered healthy food to eat freely.

The Glycemic Index of foods such as potato chips or french fries is lower than baked potatoes. Large amounts of fat tend to slow the rate of stomach emptying and therefore the rate at which foods are digested. Yet the fats in these foods contain oxidized omega 6 oils which are very harmful to the body and trans-fats which are equally harmful. These types of fats have been shown to contribute to heart and other diseases. It is important to look at the type of fat in foods. Fats in the fried foods we eat should be stable fats that do not oxidize and do not contain trans-fats. The studies done in the US from the 1950’s to the 1990’s used a large amount of fried foods in high omega 6 oils (which oxidized under heat) and significant amount of trans-fats. These studies are foundational to America’s “Fat Phobia” which has given most Americans unbalanced, erroneous health information while doing nothing to increase the longevity or health of the American people. Need a link here to Bruce Fife Article on Toxic vegetable oils.

More Information:

For more information on the Glycemic Index and its use in determining diet please check out the websites:

Dr. Mendosa http://www.mendosa.com/gilists.htm

Type 1 Diabetes Association http://www.t1da.org/_type1diabetes_diabetesproducts&supplements.htm

How to Beat Your Sugar Addiction by Rachel Leslie
http://www.pr.com/article/1058

University of Torontohttp://www.news.utoronto.ca/bin6/060623-2395.asp