Although traditional recommendations suggest a diet with 65% of calories supplied by complex carbohydrates, high-carbohydrate diets still increase blood sugar and stimulate insulin production, according to Steven Whiting, PhD. This is likely because complex carbohydrates tend to have a high glycemic load. While the glycemic index indicates how quickly a food raises blood sugar level, the glycemic load is a measure of how much sugar is in a food. Glycemic load is calculated by multiplying the number of grams of carbohydrate in a serving of food by the food’s glycemic index. Some foods such as carrots have a high glycemic index but a low glycemic load. Thus, carrots raise blood sugar quickly, but contain relatively few carbohydrates. Whole grains tend to have a lower glycemic index than white bread, but because they are rich in carbohydrates, they have a high glycemic load. Foods with a higher glycemic load are expected to cause a greater increase in blood glucose over time and thus a greater need for insulin. Long-term consumption of foods with high glycemic loads is associated with an increased risk of type II diabetes and coronary heart disease.34 Thus, both glycemic index and glycemic load are important dietary factors to consider when choosing foods to promote optimal blood sugar.
Dr. Gerald Reaven, head of endocrinology, gerontology, and metabolism at Stanford University, says, “Why trade one insulin-raising nutrient for another? It is far safer, and just as nutritious, to decrease carbohydrates and maintain protein at a reasonable level, while increasing your intake of ‘good’ unsaturated fats.”35 If fewer carbohydrates are available, the body will convert protein to glucose. This is a much slower process, so shifting the balance between carbohydrates and proteins will reduce the risk of hyperglycemia.36 Numerous studies confirm the efficacy of substituting more protein for carbohydrates.37,38 According to a September 2004 study, “increasing the protein content of the diet with a corresponding decrease in the carbohydrate content potentially is a patient-empowering way of reducing the hyperglycemia present with type II diabetes mellitus, independent of the use of pharmaceutical agents.”39
The common perception of fats is that they do little more than make us fat. The type of dietary fat is critical in determining its effects in the body. Trans fatty acids, found in hydrogenated oils in commercially made cookies, cakes, and processed foods, increase the risk of diabetes, while the polyunsaturated fats in nuts and seeds reduce risk.40 Replacing foods that are rich in trans fats with those containing polyunsaturated fat could reduce the risk of type II diabetes by nearly 40%.40 Because “good” fats such as olive oil are high in calories, however, care must be taken when planning a daily menu.
High-fiber diets are particularly helpful in promoting healthy blood sugar levels. Numerous studies confirm the importance of fiber.41-43 One study concluded, “A high level of dietary fiber . . . above the level recommended by the [American Diabetes Association], improves glycemic control, decreases hyperinsulinemia, and lowers plasma lipid concentrations in patients with type II diabetes.”44 Dietary fiber works by at least two mechanisms. Fiber-rich foods such as vegetables, beans, fruits, and whole grains take longer to chew and digest than refined foods such as white bread and sugar. Also, fiber slows the emptying of the stomach contents, promoting a feeling of fullness and balanced blood sugar levels.
Fiber should be introduced gradually into the diet because it may affect insulin and other diabetic medications, and because it takes some time for the digestive system to adjust to added fiber. The two types of fiber are soluble and insoluble. Soluble fiber slows gastric emptying and glucose release in the bloodstream. Insoluble fiber promotes bowel regularity and slows the breakdown of starch, which also has the effect of reducing blood glucose. Soluble fibers include pectin, gums, mucilages, and some hemicelluloses. Insoluble fibers include cellulose and many hemicelluloses. People commonly associate fiber with bran products, but as shown in Table 2, fiber-rich foods also include whole grains, fruits, vegetables, dried beans and peas, and nuts and seeds. Optimal daily fiber intake should include a total of 25-30 grams of soluble and insoluble fiber.
Many other foods can be helpful for controlling blood sugar. Onions and garlic are particularly beneficial foods for those with high blood sugar, and consuming 1-6 grams daily of the spice cinnamon has been shown to help reduce glucose and lipid levels.45-47
While it is important to be checked by a physician, studies have shown that diligent self-monitoring of blood sugar using currently available kits is extremely helpful for glucose management.48,49 Self-monitoring of blood glucose is an effective way to gauge your response to different foods and supplements. Using this tool, patients can play an active role in helping to optimize their blood glucose levels.