The glycemic index is back in the lime light and although we have discussed it before on the site, we like to keep our readers up to date on all subjects that they are interested in. Last month we received The Glucose Revolution, and the accompanying small booklet on the Pocket Guide to Diabetes by Miller, Wolever, Colagiuri and Powell. In the same month, we received a paper titled The glycemic index in diabetes meal planning from the 60th Scientific sessions of the ADA by Carden. To add to this we also received Control Diabetes the Easy Way, Counting Carbohydrates, by Preston, Etter, and Garner to be reviewed on this site. So readers, here we go. Lets examine how these so-called “experts” want us to examine the index and carbohydrates so you can make changes in your diet or continue just as you are now.
First, let me go over the paper as presented to the ADA. I do this because most books that I receive have a specific viewpoint that they want us to buy and change our point of view. Let’s begin by getting the facts. Then, we’ll go over what these two books have to say, and then you can make up your mind. The glycemic index is only a ranking of the potential for foods to increase blood glucose levels. It is not new and in fact has been around for 10 years. Currently, the ADA promotes a diet that states that all carbohydrates are the same with no difference in how any carb will effect blood glucose levels.
In response to those who say that eating foods that are lower on the glycemic scale, the speakers for the ADA point out that there are many blood glucose determinants including the nature of the carbohydrate, the quantity of the carbohydrate eaten, fat, protein, and other nutrients present in the foods eaten, gastric emptying time, and circadian/diurnal variations. The amount of carbohydrate makes a difference for both healthy persons as well as for those with diabetes. There is a relationship between increased carbohydrate intake and postprandial blood glucose levels up to 60 g per meal, and then it levels off.
They also report that most of the research on glycemic index has been done for breakfast meals and there may be differences for lunch and dinner. The rate of gastric emptying affects the blood glucose level as does the time the meal is eaten. For these reasons, they call for more research. The ADA does recommend the following when it comes to carbohydrates: Carbohydrate intake should be composed of whole grain, fruits and vegetables; and sugars in moderation. Carbohydrate consumption should be individualized based on postprandial blood glucose levels and should be monitored by size. Self-monitoring of blood glucose will determine the distribution of carbohydrates during the day.
Now let’s examine the philosophy of those who believe that controlling the foods we eat by their glycemic index can improve our diabetic control as espoused by the authors of The Diabetic Revolution. These folks see the glycemic index as giving us the true story about carbohydrates and the blood glucose connection. Their book negates the need to look at simple and complex carbohydrates when planning meals; it looks only at the glycemic index of the carbohydrate.
In type 2 diabetes, the authors point to the fact that foods low on the glycemic index need less insulin to metabolize them and, in the process, they claim that this type of diet improves the body’s sensitivity to insulin so that you use the insulin you have more efficiently. It is their assertion that slow digestion and gradual rise and fall in blood glucose after a meal low in glycemic index foods will help control blood glucose levels in people with diabetes. Now let me share with you their suggestions for an optimum diet for people with diabetes. Eat plenty of whole grain foods, vegetables and fruits. Sound familiar? Eat small amounts of fats, especially saturated fats. Eat a small amount of sugar and sugar-containing foods. Use alcohol sparingly and cut down on sodium intake.
There is information on how to assess your carbohydrate needs and how to overhaul your diet.. There is a good chapter on “How Well are You Eating Now?” as well as a chapter on stocking your pantry. There is a glycemic index table as well as suggestions for meal substitutions. The larger book The Glucose Revolution, which has chapters for weight loss, heart disease, diabetes and athletics and the index, has recipes and sample menus.
Did I think the book was of value? The answer is yes because it does have a good index and that is helpful. I went on their diet, but since I already ate a diet low in glycemic index foods most of the time, I saw little change. I was, however, able to choose foods with ease using the ratings. The recipes are simple in nature and appear easy to prepare. I question their taste, but then you know the kinds of foods and recipes we have here at blogdiabetes.com, so please take that criticism for what it’s worth. Now let me share one thing that did jump out at me and which concerns me. The definition of type 1 diabetes states that “…the pancreas does not produce enough insulin…” Those of us who take our blood glucose levels 4-6 times a day and jockey our meals with insulin injections know that we began this regime the day our last beta cells died and we no longer produced insulin. This may be a small thing, but I need to trust everything in a book that claims to have the answer to controlling the disease with which I must battle every day.
So what are the global concerns about the glycemic index? Many people have questioned the reproducibility of results. There is inadequate applicability to mixed meals, and only modest improvement in postprandial glucose levels. Also noted is the complexity and difficulty of a low-glycemic index diet and the restriction of food variety of these diets as well as the public’s preference for high-fat, high glycemic index foods. The proponents of using the low glycemic index food diet counter with the fact that they have found little difference in blood glucose levels within people when tested with the same carbohydrate foods on different occasions.
They see differences in blood glucose levels as being due to glucose intolerance within different people. They cite 14 long-term studies conducted in Canada, France, the United Kingdom, Sweden, and Australia. In these crossover studies all diabetic subjects had improved HbA1c averaging 11%. These proponents suggest that to make the transition easier, that you substitute 1 low-glycemic food for 1 high-glycemic food in each meal.
To make a major change they suggest to keep it simple, i.e. this for that. Swap half of the total carbs from high to low-glycemic index foods. Focus on foods that contribute most to CHO such as bread, breakfast foods, and potatoes when making changes.. Currently the GI, or glycemic index, is being considered for inclusion in nutrition labeling in Australia and a new GI food symbol has been registered in Australia and North America. Another tool is under development which will help monitor portion size and that is called the glycemic equivalent exchange.