Diabetes & Glycemic Index, Ranking of Carbohydrates

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22 June 2010 No Comment

What is the Glycemic Index?

Not all carbohydrate foods are created equal, in fact they behave quite differently in our bodies. The glycemic index or GI describes this difference by ranking carbohydrates according to their effect on our blood glucose levels. Choosing low GI carbs – the ones that produce only small fluctuations in our blood glucose and insulin levels – is the secret to long-term health reducing your risk of heart disease and diabetes and is the key to sustainable weight loss.

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 after eating. Foods with a high GI are those which are rapidly digested and absorbed and result in marked 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, and have proven benefits for health. Low GI diets have been shown to improve both glucose and lipid levels in people with diabetes (type 1 and type 2). They have benefits for weight control because they help control appetite and delay hunger. Low GI diets also reduce insulin levels and insulin resistance.

Recent studies from Harvard School of Public Health indicate that the risks of diseases such as type 2 diabetes and coronary heart disease are strongly related to the GI of the overall diet. In 1999, the World Health Organisation (WHO) and Food and Agriculture Organisation (FAO) recommended that people in industrialised countries base their diets on low-GI foods in order to prevent the most common diseases of affluence, such as coronary heart disease, diabetes and obesity.

What are the Benefits of the Glycemic Index?

Eating a lot of high GI foods can be detrimental to your health because it pushes your body to extremes. This is especially true if you are overweight and sedentary. Switching to eating mainly low GI carbs that slowly trickle glucose into your blood stream keeps your energy levels balanced and means you will feel fuller for longer between meals.

Low GI diets help people lose and manage weight
Low GI diets increase the body’s sensitivity to insulin
Low GI carbs improve diabetes management
Low GI carbs reduce the risk of heart disease
Low GI carbs improve blood cholesterol levels
Low GI carbs can help you manage the symptoms of PCOS
Low GI carbs reduce hunger and keep you fuller for longer
Low GI carbs prolong physical endurance
High GI carbs help re-fuel carbohydrate stores after exercise

How to Switch to a Low GI Diet

The basic technique for eating the low GI way is simply a “this for that” approach – ie, swapping high GI carbs for low GI carbs. 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.

Use breakfast cereals based on oats, barley and bran
Use breads with wholegrains, stone-ground flour, sour dough
Reduce the amount of potatoes you eat
Enjoy all other types of fruit and vegetables
Use Basmati or Doongara rice
Enjoy pasta, noodles, quinoa
Eat plenty of salad vegetables with a vinaigrette dressing

To determine a food’s GI rating, measured portions of the food containing 10 – 50 grams of carbohydrate are fed to 10 healthy people after an overnight fast. Finger-prick blood samples are taken at 15-30 minute intervals over the next two hours. These blood samples are used to construct a blood sugar response curve for the 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 by dividing the AUC for the test food by the AUC for the reference food (same amount of glucose) and multiplying by 100. The use of a standard food is essential for reducing the confounding influence of differences in the physical characteristics of the subjects. The average of the GI ratings from all ten subjects is published as the GI of that food.

The GI of foods has important implications for the food industry. Some foods on the Australian market already show their GI rating on the nutrition information panel. Terms such as complex carbohydrates and sugars, which commonly appear on food labels, are now recognised as having little nutritional or physiological significance. The WHO/FAO recommend that these terms be removed and replaced with the total carbohydrate content of the food and its GI value. However, the GI rating of a food must be tested physiologically and only a few centres around the world currently provide a legitimate testing service. The Human Nutrition Unit at the University of Sydney has been at the forefront of glycemic index research for over two decades and has tested hundreds of foods as an integral part of its program. Jennie Brand Miller is the senior author of International Tables of Glycemic Index published by the American Journal of Clinical Nutrition in 1995 and 2002.

The Glycemic Index Foundation and the GI Symbol Program

Today’s savvy supermarket shoppers look for the GI Symbol. They know that they need to put those smart low GI carbs into the trolley to manage their blood glucose levels, reduce their risk of diabetes and heart disease, and maintain a healthy weight.

Backed by the Glycemic Index Foundation, a collaboration between the University of Sydney, the Juvenile Diabetes Research Foundation of Australia, and Diabetes Australia, the GI Symbol Program leads the way in helping everybody make healthier food choices every day for every meal for their long term health and well being.

When you pick a food product that carries the GI Symbol, you know that the GI value stated near the nutrition information panel is accurate and that you have made a healthy choice for that food category from breads and breakfast cereals to fruit, or yoghurt. This is because to earn the GI Symbol, a food not only has to be low GI, it must also meet our strict nutrition criteria for energy (calories/kilojoules), fat, saturated fat, sodium, and where appropriate, fiber and calcium. Save time reading the entire pack because we’ve done the hard work for you.

There is now an even easier way to identify healthy low GI products in your local supermarket: the all new, refreshed and brighter GI Symbol is the only authentic GI Symbol that is based on over 25 years of scientific research.
The new GI Symbol still carries the same trusted credentials as the old one, and the products that carry the Symbol still meet the same strict nutrition criteria – but now it’s even easier for people to shop for themselves and their families and choose foods to help them follow a healthy diet. Foods and drinks carrying this symbol:

Meet strict nutrition criteria for energy (calories/kilojoules), fat, saturated fat, sodium, and where appropriate, dietary fibre and calcium
Help maintain a healthy body weight
Help manage blood glucose (sugar) levels
Reduce the risk of diabetes and heart disease

The scientific evidence supporting the health benefits of a healthy low-GI diet is overwhelming. Healthy low GI-foods can sustain your energy levels for longer, keep you feeling satisfied for longer, help you lose body fat, maintain lean muscle tissue, and improve your cholesterol, to name just a few.

You can be confident that when you choose a product that carries the GI Symbol, the GI value stated near the nutrition information panel is accurate and you’ve made a healthy choice for that food category – from breads and muesli bars, to fruit and yoghurt.

The new GI Symbol started to appear on products (Tip Top 9 Grain and Burgen breads) on supermarket shelves from the end of September 2009, and will continue to be phased in over the next 12 months, so keep your eye out for it to make your healthy choices, easy choices.

The Glycemic Index and Dieting

by: Protica Research

The field of nutrition is awash with charts, tables, diagrams, models, acronyms, and abbreviations; more than the average person can memorize. As such, one often comes across someone who has simply burnt out trying to keep track of how much to eat, when to eat it, how to find the calories from fat, the RDI, the DV, and so on. There is an overkill of useful information within the nutrition field, and it can ironically provoke one to grow weary and exhausted, tune out, and go grab a fast food burger.Yet every once in a while, a concept within the nutrition field emerges that truly demands attention. Over a decade ago, the USDA’s “Food Pyramid” was one such concept because it helped eaters discover how many gaps existed in their typical daily diet. Now, as the Food Pyramid begins to take a new shape, and as the nutrition field works to establishes itself as the most important branch of health care in the 21st century, an invention called the Glycemic Index is taking center stage.The Glycemic Index (GI) is not new; it has been around for more than 2 decades. Yet until recently, its exposure beyond the world of diabetes has been limited.The Glycemic Index indicates how “high” or “low” blood sugar levels change in response to carbohydrate intake. A “high” Glycemic Index indicates carbohydrates with a swift breakdown, whereas a “low” Glycemic Index indicates carbohydrates with slow, gradual breakdown. Both terms are of equal importance to diabetics, because there are times with high Glycemic Index foods are required, and times where low Glycemic Index foods are required.Indeed, the Glycemic Index itself is not new, but its application far beyond the borders of a diabetic dialogue is notable; especially for dieters.People striving to lose weight often face a nemesis much tougher than establishing an exercise regimen or introducing healthier foods into their diet. The problem is one of energy. Many dieters are surprised – and disturbed – to learn that their diet program is causing them to lose more than inches and pounds: they are losing energy.This is often expressed as a complaint, as in “I’m feeling weak”, or even “I can’t stay awake”. Many dieters and those advising them have erroneously chalked this up to a matter of attitude, or will power, or some non-biological cause.The plain truth is that many dieters have been oblivious to the Glycemic Index, and hence, to the fact that many of the diet foods they have eaten – or are eating right now – score very high Glycemic Index levels. As such, these foods are providing a quick boost to blood sugar levels, and then setting up the dieter for the inevitable fall. This is because high GI foods typically increase blood sugar values, which in turn trigger the hormone insulin to clear sugar from the blood. Since blood sugar (a.k.a. glucose) largely dictates the body’s energy levels, it stands to reason that this process manifests as an initial boost in energy, and then as a depletion of energy. This rise and fall of blood sugar – and energy – is often described by dieters using a “roller-coaster” analogy: one minute they feel confident and strong, and the next, they are about to pass out and require some kind of stimulant in order to make it through the day.Regrettably for many dieters, that stimulant is usually more high Glycemic Index foods, such as sugary snacks or soft drinks. It is easy to see how this experience can lead an individual to stop dieting. After all, before the diet, the individual was merely gaining weight. On the diet, the individual is gaining weight and is exhausted for most of the day. It is better to quit the diet.

The above scenario only takes place, however, when a dieter unwittingly eats high Glycemic Index foods. Research has shown that low Glycemic Index foods, which raise blood sugar levels much more gradually than high Glycemic Index foods, are very helpful for dieters. This is because a dieter will experience less of a “roller-coaster” ride while on the diet, and furthermore, will be less inclined to snack because energy in the form of blood glucose is being released slowly and gradually. Low Glycemic Index foods are much more efficient sources of energy than high Glycemic Index foods, because the body needs less insulin to convert food into energy.

Despite the growing awareness that low Glycemic Index foods are beneficial, the world of diet foods has not kept pace. This is because many manufacturers are searching frantically to find low Glycemic Index carbohydrates sources for their products, and overlooking a basic, simple fact: the lowest possibly Glycemic Index is no carbohydrates at all.

These zero-carbohydrate/zero sugar nutritional supplements – which are quite rare in the market – do not deliver any sugar to the bloodstream. As a result, dieters do not have to worry about riding the “roller coaster” of energy spikes and pitfalls.

Yet there is an even greater benefit for dieters who choose a ‘zero sugar’ nutritional supplement. If that low Glycemic Index nutritional supplement is rich in complete protein, then it will act as a sort of antidote to high GI foods by helping to combat their adverse consequences.

For example, a dieter who eats a high Glycemic Index candy car can mitigate the roller-coaster spike in blood sugar levels by eating a nutritional supplement that has very low Glycemic Index and has a rich source of complete protein. This is because the protein in the nutritional supplement mixes with the high Glycemic Index of the candy bar, and effectively lowers the overall Glycemic Index. This is welcome news to dieters who would otherwise be seeing those extra carbohydrates transformed by insulin into triglycerides, and stored in adipose tissue; also known as body fat.

Currently, only a handful of nutritional supplements are designed to offer zero carbohydrates and thus score as low as possible on the Glycemic Index. And of these zero-carbohydrate products, even fewer offer a rich source of complete protein that effectively helps counter the blood sugar spike impact of high Glycemic Index foods.

It is inspiring to note that Glycemic Index is getting some well-deserved attention from outside the diabetic community, where it has helped millions of people eat wisely. Now, dieters and obese people can enjoy the wisdom that this index promotes.

The Glycemic Index: Key To Weight Loss Or Just Another Diet Gimmick?

by: Tom Venuto

Copyright 2005 Tom VenutoThe glycemic index (GI) is a scale that measures how quickly carbohydrate foods are broken down into glucose. The original purpose for the glycemic index was to help diabetics keep their blood sugar under control. The glycemic index has recently attracted a lot of attention in the bodybuilding, fitness and weight loss world and has even become the central theme in numerous best-selling diet books as a method to choose the foods that are best for losing weight.According to advocates of the glycemic index system, foods that are high on the GI scale such as rice cakes, carrots, potatoes, or grape juice are “unfavorable” and should be avoided because high GI foods are absorbed quickly, raise blood sugar rapidly and are therefore more likely to convert to fat or cause health problems.Instead, we are urged to consume carbohydrates that are low on the GI scale such as black eye peas, old fashioned oatmeal, peanuts, apples and beans because they do not raise blood sugar as rapidly.While the GI does have some useful applications, such as the use of high GI foods or drinks for post workout nutrition and the strong emphasis on low GI foods for those with blood sugar regulation problems, there are flaws in strictly using the glycemic index as your only criteria to choose carbs on a weight loss program.For example, the glycemic index is based on eating carbohydrates by themselves in a fasted state. If you are following effective principles of fat-burning and muscle building nutrition, you should be eating small, frequent meals to increase your energy, maintain lean body mass and optimize metabolism for fat loss. However, since the glycemic index of various foods was developed based on eating each food in the fasted state, the glycemic index loses some of its significance.In addition, when you are on a diet program aimed at improving body composition (losing fat or gaining muscle), you will usually be combining carbs and protein together with each meal for the purposes of improving your fat to muscle ratio. When carbs are eaten in mixed meals that contain protein and some fat, the glycemic index loses even more of its significance because the protein and fat slows the absorption of the carbohydrates (as does fiber).Mashed potatoes have a glycemic index near that of pure glucose, but combine the potatoes with a chicken breast and broccoli and the glycemic index of the entire meal is lower than the potatoes by itself.

Rice cakes have a very high glycemic index, but if you were to put a couple tablespoons of peanut butter on them, the fat would slow the absorption of the carbs, thereby lowering the glycemic index of the combination.

A far more important and relevant criteria for selecting carbs – as well as all your other foods, proteins and fats included – is whether they are natural or processed. To say that a healthy person with no metabolic disorders should completely avoid natural, unprocessed foods like carrots or potatoes simply because they are high on the glycemic index is ridiculous.

I know many bodybuilders (myself included) who eat high glycemic index foods such as white potatoes every day right up until the day of a competition and they reach single digit body fat. How do they do it if high GI foods “make you fat?” It’s simple – high GI foods DON’T necessarily make you fat – choosing natural foods and burning more calories than you consume are far more important factors. Although it’s not correct to say that all calories are created equal, a calorie deficit is the most important factor of all when fat loss is your goal.

The glycemic index is clearly not a “gimmick” and should not be completely disregarded, as it is a definitely a legitimate nutritional tool. Is it a good idea to eat low GI foods in general? Sure. Is eating high GI foods after your workouts a good idea? Absolutely. But diet programs which hang their hats on glycemic index alone as the “miracle solution” are just another example of how one single aspect of nutrition can be used as a “hook” in marketing and said to be the “end all be all” of fat loss, when it’s really only one small piece of the puzzle.

Eating Low glycemic index foods alone does NOT guarantee you will lose fat. You have to take in the bigger picture, which includes calories/energy balance, meal timing and frequency, macronutrient composition, choice of processed versus refined foods as well as how all these nutritional factors interact with your exercise program.