Get to Know Your Carbohydrates

review by Katherine Duff

, by Jennie Brand-Miller, PhD; Thomas Wolever, MD; Kaye Foster-Powell; and Stephen Colagiuri MD

Da Capo Press; 11 Cambridge Center, Cambridge, MA 02142

©2010; softcover; $16.95; 383 pp.

The concept of the glycemic index has entered the fabric of many diets in the last couple decades. Some of the diets explain the concept in shorthand, but for the comprehensive explanation of the glycemic index (GI), readers can look to The Low GI Handbook. In this new and revised edition in The New Glucose Revolution series, we learn about new research that is uncovering the importance of blood glucose levels in the management of more and more diseases and prevention as well. The authors of some of the previous books, Jennie-Brand-Miller PhD; Thomas Wolever MD; Kaye Foster-Powell; and Stephen Colagiuri MD, have contributed to this handbook.

In the “Overview,” we learn that the glycemic index was introduced by Dr. David Jenkins in 1981 in an effort to assist people with diabetes in their diet choices. His research found that the established classifications of carbohydrates, simple for sugars and complex for starches, failed to accurately account for the effect of various foods on the blood glucose levels. Further testing allowed him to classify in a numerical scale of 0 to 100, how fast the carbohydrates of given foods entered the bloodstream. Pure glucose, which is absorbed the fastest, is given the glycemic index of 100. All other foods are rated as a percentage of the 100: the higher the number, the faster the absorption resulting in higher glucose blood levels. Some of the findings contradicted the conventional wisdom. Sugars in fruits did not spike glucose levels as previously believed, and starches that were thought to be digested slowly were actually absorbed quickly. There is no easy way to identify the glycemic index of foods, so each must undergo testing. Fluctuating and consistently high blood glucose levels are a problem for people with diabetes and, as the authors describe, everyone else as well. Carbohydrates stimulate the secretion of insulin more than any other nutrient. A diet of foods high on the glycemic index will cause high blood glucose levels that require the pancreas to work extra hard to secrete the necessary insulin. Too much overwork of the pancreas can lead to type 2 diabetes in people genetically prone to the disease. High insulin levels increase the risk of heart disease, among other conditions.

Examples of how high glucose levels in the blood can affect the heart can be found in the discussions of C-reactive protein (CRP) and metabolic syndrome. The CRP is a measure of chronic low-grade inflammation in the body, a known risk factor for heart disease. Studies have shown that women who consume high GI diets have higher CRP results. Metabolic syndrome is a collection of endocrine abnormalities that represent a serious risk of heart attack or stroke. A raised glucose level is one of those factors and is an indication of insulin resistance. This is when the liver and muscle cells resist the uptake of glucose, prompting the pancreas to secrete even more insulin. A diet of high glycemic foods leads to this problem developing.

Another condition that the authors mention is polycystic ovarian syndrome (PCOS). We learn that most women with PCOS have insulin resistance. Insulin stimulates the growth and multiplication of cells in the ovary so the ever-increasing secretion of insulin leads to a vicious cycle of hormonal imbalance. The hormone imbalance, which is responsible for the symptoms, can be managed through maintenance of low blood glucose and insulin.

In addition to the many health conditions discussed, there is advice about managing the type of carbohydrates in the diet to achieve optimal performance in sports and exercise. Possibly, though, the most vital section of the book concerns the foods that we provide children and how to educate them to make better diet choices. As the authors note, our modern diet is contributing to the increased incidence of diseases that high blood glucose levels encourage. That these illnesses are developing in younger people now should be a real wake-up call to start children on the more healthful path

The last half of the book contains the information that we need to put into practice the low glycemic diet. The list of foods and their rank on the glycemic scale would be the place to start. Some readers may be so indoctrinated with the “low-carbohydrate” edict of older diets that it may take some study to differentiate the glycemic rating from the carbohydrate content that we have come to know.

The next step is to design meals that maintain low blood glucose levels. In practice, a meal can contain high- and low-glycemic foods and the effect on the blood glucose levels would be a weighted average. The GI is not added up for the day like calories, but is used to create a balanced meal or snack. The authors supply sample menus and recipes that should familiarize the reader with the new process.

The diseases discussed in this book are those that top the list of our nation’s most common health problems – heart disease and diabetes. Our modern diet of processed foods, bad fats, salt, and sugars is proving to be a major contributor to these illnesses. This book offers a roadmap for using a diet that could prevent them in the first place. In some examples in the book, people have improved their overall health, lost weight, and changed troublesome lab results back to the normal range. This book would be a good place to start for those who want to update their understanding of carbohydrates.

Pearl: “One of the most important ways in which our diet differs from that of our ancestors is the speed of carbohydrate digestion and the resulting effect on our blood glucose and hence every cell of the body.”