The time it takes for our food to influence our blood sugar levels has a great influence on our health. This is important because frequent, rapid changes in blood sugar increase the risk of developing type two diabetes, and can eventually contribute to heart disease and strokes in some people. Some scientists have even associated blood sugar fluctuations with an increased risk of cancer.
In addition, people often find that a rapid increase in blood sugar is followed by a blood sugar low, as the initial rise causes the pancreas to release insulin; the body then reduces blood sugar levels by storing the excess sugars.
A blood sugar low can result in cravings for more foods with a high sugar content, leading to a situation where a person’s blood sugar rises and falls dramatically throughout the day. It is common for people falling into this pattern to put on excess weight. Many people have found it easier to lose weight by eating foods that encourage their blood sugar to rise slowly, which reduces the risk of craving sweets and subsequently converting sugar to fat.
Knowing which foods will maintain stable blood sugar levels is essential for anyone trying to control diabetes through diet. For this reason it is helpful to rank foods according to the rate at which they change blood sugar levels. Dr. David Jenkins at St. Michael’s Hospital in Toronto first studied and created the glycemic index (GI), which proved to shed surprising new light on which foods actually have the greatest effect on our blood sugar levels.
The GI is a system of measuring how quickly eating different carbohydraterich foods increases blood sugar levels. The higher the number, the quicker the blood sugar response; so a low-GI food will cause a slow rise, while a high- GI food will trigger a dramatic blood sugar spike, often followed by a blood sugar low. A GI of seventy or more is high, a GI of between fifty-six and sixty-nine is medium, and a GI of fifty-five or less is considered low.
The glycemic load (GL) is another way to assess the impact of carbohydrate consumption that takes the glycemic index into account, but gives a fuller picture. A GI value tells you only how rapidly the carbohydrate component of a particular food turns into sugar. It doesn’t tell you how much of the carbohydrate is in a serving of a particular food. You need to know both things to understand a food’s effect on blood sugar. For example, the carbohydrate in watermelon has a high GI, but because there’s not a lot of it, watermelon’s glycemic load is relatively low. A GL of twenty or more is high, a GL between eleven and nineteen is medium, and a GL of ten or less is low.
The idea of maintaining stable blood sugar levels has long been an important aim of macrobiotic practitioners; in this sense, macrobiotics could be claim to be the original GI diet. Foods with a GI of fifty-five or less are considered ideal, and, looking through the table below, you will see most whole, living macrobiotic foods have a GI of fifty-five or less. The exceptions to this are millet, apricots, raisins, watermelon, broad beans, pumpkin, beets, potatoes, sweet potatoes, and rutabagas. You also need to consider the amount of carbohydrate a food will convert into blood sugar, the glycemic load or GL. If the GL is ten or less, it is considered low, so foods like apricots,watermelon, broad beans, pumpkin, beets, and rutabagas may increase your blood sugar quickly, but do not raise it particularly far, as there are not sufficient carbohydrates in a typical serving.
From a macrobiotic perspective there’s another issue, and that is the effect of taking in the energies of these high GI or GL foods and the influence of unstable blood sugar levels on our emotions. As our blood sugar reaches a high, it is common to feel hyperactive, unfocused and slightly out of control, while during a blood sugar low it becomes easier to feel depressed, pessimistic, and drained. Rapidly changing blood sugar levels seems to particularly affect children, precipitating tantrums, later followed by feeling withdrawn.
Looking through the information and tables below, interesting patterns emerge.
1. Whole grains have a lower GI than processed grains. For example, white rice has a GI of sixty-four, while brown rice registers at fifty-five.
2. You can reduce the GI of brown rice by mixing it with another low-GI grain such as whole barley.
3. Puffed grains like rice cakes or puffed rice cereals have a much higher GI than the original whole grain.
4. The longer a food is cooked, the higher the GI. For example, the natural sugars in pasta cooked al dente are absorbed more slowly than when pasta is overcooked. Spaghetti boiled in salted water for eleven minutes has a GI of fifty-nine, while boiling for sixteen minutes gives it a GI of sixty-five.
5. Most vegetables, beans, nuts and seeds have a GI that is too low to be considered significant.
6. Baking or frying foods raises their GI. Potatoes have a GI of eighty-five when baked, seventy-five when fried, and fifty when boiled.
7. Fish, eggs, and meat have GIs that are too low to be considered relevant.
The glycemic index is complicated and cannot be generalized to all people.
Different people will have different reactions to food. Your body’s response to food will vary according to several factors, including your age, activity level, insulin levels, and metabolism; the time of day you’re eating; the amount of fiber and fat in the food; whether the food has been processed; what you ate along with the food; the ratio of carbohydrates to fat and protein; and how the food was cooked.
For example, a child running around outdoors will burn of blood sugar quickly, whereas an adult sitting in a warm office will not. Food high in GI or GL will not necessarily affect an active child. So while these tables are an interesting guide to how different foods can affect us, and while they can be useful for anyone wishing to lose weight or moderate their moods, they are not recommended as the sole basis for choosing foods.
My own experience has been that eating whole foods greatly improves my endurance, consistency of mood, and emotional stability. With whole, unprocessed foods, I find it easier to maintain my ideal weight and go through the day without cravings for snacks. For these reasons I would prefer to have fruit, nuts, or seeds than a healthy cookie or energy bar. By simply focusing on predominantly whole, unprocessed food, my diet naturally becomes low in terms of its GI and GL.
As always, it’s for you to try out and see for yourself how you feel after a few weeks of choosing foods a certain way.
Most vegetables have too low a GI to consider. For example, artichokes, avocados, asparagus, bok choy, broccoli, brussels sprouts, cabbage, carrots, cauliflower, celery, cucumbers, eggplant, green beans, green peas, leeks, lettuce, mushrooms, onions, olives, peppers, spinach, squash, tomatoes, yams, and zucchini all have GIs of less than 55.
From Macrobiotics for Life: A Practical Guide to Healing for Body, Mind, and Heart by Simon Brown, published by North Atlantic Books, copyright © 2009 by Simon Brown. Reprinted by permission of publisher.