High blood sugar, known as hyperglycemia, is the hallmark of diabetes. People who are diabetic either produce insufficient amounts of insulin, which is needed to transport sugar from the bloodstream into cells, or their cells don’t respond properly to insulin. Either way, too much sugar remains in the blood and not enough is available for cellular energy production. Some carbohydrate-based foods are quickly metabolized into sugar, which worsens diabetic conditions and also causes insulin spikes and symptoms in non-diabetics. These foods should be avoided by diabetics and carefully moderated by non-diabetics. Consult a nutritionist about which foods to avoid to maintain healthy blood sugar levels.
Implications of High Blood Sugar
Glucose is the simple sugar that circulates in your blood and provides your cells with energy. As a rule, fasting blood glucose levels should be between 70 and 90 milligrams per deciliter. Levels above 120 are usually considered mildly hyperglycemic. For comparison, diabetics who are not on medication often have glucose levels between 180 and 250 milligrams per deciliter or higher. Non-diabetics can also experience temporary spikes in blood glucose levels if they eat too much food that has a high glycemic index, which is a measure of how quickly carbohydrates are reduced or metabolized to glucose. Too much sugar in the blood is toxic to tissues, especially small nerves and blood vessels, and can lead to dramatic fluctuations in mood, energy levels and cognition.
Sugary Foods and Desserts
Candy, milk chocolate, donuts, cookies and most desserts such as ice cream, cakes and pies are very high in refined sugar and should be avoided or minimized if high blood glucose is a concern for you. Highly refined sugars such as high fructose corn syrup are digested and metabolized rapidly, which causes a “sugar rush” and triggers an abnormally large release of insulin, at least in those who have a normally functioning pancreas. In non-diabetics, the quick and dramatic rise and fall of blood sugar leads to erratic moods and behavior, especially in children. In diabetics, the rise in blood sugar if not adequately dealt with, contributes to tissue damage and other symptoms.
Refined grains, such as white rice, white bread, highly processed breakfast cereals and pasta made from white flour, are other types of carbohydrates that quickly metabolize into glucose and lead to a spike in blood sugar levels. Avoiding these foods and replacing them with whole-grain alternatives, such as brown rice, multi-grain bread and less refined breakfast cereals, are good strategies to prevent hyperglycemia, according to the book “Contemporary Nutrition: Functional Approach.” Whole-grain foods contain more fiber and take longer to digest, which slowly releases the glucose into your bloodstream.
Excessive Fruit Consumption
Fruits contain a wide variety of healthy nutrients such as vitamins, minerals and antioxidants, but they also contain fructose, which is readily metabolized into glucose. For example, eating ripe bananas, blueberries and pineapples can spike blood glucose levels if consumed in excess, so practicing moderation is a good strategy. Furthermore, combining fruits higher in fiber, such as apples, pears, prunes and blackberries, can slow down digestion and have a smaller impact on blood glucose levels and insulin secretion.
- Harrison's Principles of Internal Medicine; A. Fauci et al.
- Contemporary Nutrition: Functional Approach; Gordon M. Wardlaw et al.
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.