In recent years, new research has led to key changes in the nutrition advice clinicians provide to people with diabetes. Despite recent advances, there are still numerous misconceptions about the role of sugars in the diet for people with diabetes.

General Nutrition Goals

According to the Canadian Diabetes Association's (CDA) 2013 Clinical Practice Guidelines, a multifaceted approach by a wide array of health care providers (e.g., dietitians, nurses) is required to improve diabetes management. Balancing nutrition therapy and physical activity with insulin and/or oral medications is critical to improvements in blood glucose control.

The CDA states that "Nutrition therapy is an integral part of the treatment and self management of diabetes. The goals of nutrition therapy are to maintain or improve quality of life and nutritional and physiological health, and to prevent and treat the acute and long-term complications of diabetes, associated comorbid conditions and concomitant disorders".

Carbohydrates

Carbohydrate recommendations for people with diabetes are comparable to recommendations for the general public for healthy eating. The Canadian Diabetes Association (CDA) suggests that dietary carbohydrate from a variety of sources should provide approximately 45-60% of an individual's daily energy intake.

The total amount of carbohydrate, preparation and cooking methods, as well as carbohydrate characteristics like particle size and starch structure can influence the body's response to carbohydrate in food. According to the CDA, choosing low-glycemic index foods more often may help optimize glycemic (blood glucose) control. It is for this reason that the glycemic index may be a useful tool for managing blood glucose in people with diabetes.

Individuals' using insulin therapy should adjust their insulin based on the carbohydrate (starch and sugar) content of their meals and snacks. Nutrition counseling by a registered dietitian, along with education on meal planning and matching insulin to carbohydrate content is essential.

Sugars

It was previously believed that sucrose (table sugar) and other sugars contributed to the development of diabetes and that people with diabetes should avoid sugars. This belief was based on the assumption that sugars were more rapidly digested and absorbed than other carbohydrates and would therefore aggravate hyperglycemia. In fact, numerous studies show that the sugars content of foods is not a good predictor of glycemic response.

Recent Canadian, American and International dietary recommendations have concluded that sugars do not contribute to the development of diabetes and can be included as part of healthy meal plans for people with type 1 and type 2 diabetes.

The Canadian Diabetes Association (CDA) does not recommend the avoidance of sugars. The CDA recommends that in addition to naturally occurring sugars in fruits, vegetables and dairy products, sugars added to foods can be substituted for other carbohydrates up to 10% of total daily energy requirements without evidence of deleterious effects on blood glucose or lipid control.

Fibre

Dietary fibre has been associated with improved health in people with diabetes. Evidence suggests that the inclusion of soluble fibre (e.g., psyllium, barley) in the diet can reduce serum cholesterol and improve blood glucose control. Cereal fibre may reduce the risk for coronary heart disease. All Canadians are advised to increase their dietary fibre intake from a variety of foods by following Canada's Food Guide. The Canadian Diabetes Association recommends an intake of 25-50 grams of fibre per day for people with diabetes, due to the recognized beneficial effect of fibre intake on glycemic control and blood lipids.

Glycemic Index

The glycemic index (GI) was developed by Canadian researchers as a tool to measure the body's blood glucose response to the ingestion of carbohydrate-containing foods. GI is a scale that ranks carbohydrate foods based on how much they increase blood glucose levels about 2-3 hours after eating. The GI uses a numbering system to label foods as low GI (less than 55), medium GI (55-70) or high GI (more than 70). Foods with a high GI result in a larger increase in blood glucose than foods with a low GI. Table sugar (sucrose) has a medium GI.

The GI was originally created to help people with diabetes control their blood glucose levels. The Canadian Diabetes Association recommends that people with diabetes choose low and medium GI foods more often than high GI foods. However, it is important to note that the GI system does have some limits including:

  • The GI of a single food may change when it is eaten with other foods as part of a meal or snack
  • High GI foods can also be part of a healthy diet. For example, parsnips, winter squash and rutabaga have a high GI but are also rich in fibre, vitamins, and minerals.
  • The GI of a food may vary depending on how it is cooked or where it was grown.

The concept of the glycemic index challenges the traditional view that people with diabetes should avoid sugars. In the past, clinicians believed that sugars were detrimental to people with diabetes because they were thought to cause a rapid and larger increase in blood glucose than starchy foods such as potatoes and bread. However, it was discovered that some sugars actually have a lower GI value than many starchy foods. It was also found that sucrose, or table sugar, in moderate amounts does not compromise blood glucose control.

Glycemic Index of Various Foods

  Low GI (<55) Medium GI (55-70) High GI (>70)
Grains and Starches All cereals provide energy, vitamins and minerals. Whole grain and bran cereals also provide fibre.
Cereals All Bran™, Steel Cut Oats, Oat Bran Shredded Wheat™, Quick Oats Rice Krispies™, Corn Flakes™, Bran Flakes™, Cheerios™, Instant Oats
Breads Stone ground Whole Wheat Bread, 12-Grain / Mixed Grain Bread, Pumpernickel Bread Whole Wheat Bread, Rye Bread, Sourdough Bread White Bread, White Bagel, Kaiser Roll
Grains/ Pasta Pasta (cooked "al dente"), Converted or Parboiled Rice Basmati Rice, Brown Rice, Couscous Instant Rice
Fruits and Vegetables High GI vegetables, such as parsnip, rutabaga and winter squash, are also rich sources of vitamins, minerals and fibre.
Starchy Vegetables Sweet Potato, Green Peas, Yam Raw Carrots, Baked Potato with Skin, New Potato, Corn Baked Potato without Skin, Mashed Potato, Parsnip, Rutabaga, Winter Squash
Fruit and Fruit Juices Apple, Orange, Strawberries, Peach, Cherries, Grapes, Apple Juice, Orange Juice, Grapefruit Juice Banana, Raisins, Apricots, Grape Juice, Cranberry Cocktail Watermelon, Dried Dates
Milk Products Milk products provide important minerals for bone health including calcium, phosphorus and magnesium.
  Milk, Plain Yogurt, Sweetened Yogurt, Chocolate Milk Sweetened Condensed Milk  
Legumes Legumes, including beans and lentils, are an excellent source of protein and fibre.
  Lentils, Kidney Beans, Chick Peas, Baked Beans    
Sugars Maple syrup, brown sugar, honey and white sugar (sucrose) are all mainly carbohydrates and provide the same number of calories (4 Calories per gram).
  Fructose Table Sugar (Sucrose), Brown Sugar, Honey Glucose (GI=100)

Source: International table of glycemic index and glycemic load values: Am J Clin Nutr 2002;76:5-56.

For more on the glycemic index, please see CSI resources The Glycemic Index: Clinical and Public Health Significance (pdf) and Understanding the Glycemic Index (pdf).

Weight Management

An estimated 80% to 90% of people with type 2 diabetes are overweight or obese. However, most cases of type 2 diabetes can be prevented or delayed with better weight management. In fact, weight management improves all aspects of diabetes control including blood glucose, blood lipids and hypertension.

According to the Canadian Diabetes Association (CDA) a small weight reduction of 5-10% of initial body weight is all that is needed to fuel these improvements. Thus, achieving a 'goal weight' is not essential. Further, the CDA recommends that weight loss be slow and gradual – and that the focus for people with diabetes be on adopting a healthy lifestyle by balancing food intake and daily physical activity.

For more on weight management, click here.

Physical Activity and Exercise

It is well established that exercise is an important part of healthy living, providing numerous health benefits and contributing to improved confidence and vitality. In people with type 2 diabetes, physical activity can also boost insulin sensitivity and blood glucose control, improve lipid profiles, and lessen the need for medication.

Physical activity can also assist people with diabetes in losing weight. This in itself can improve blood glucose control. However, with weight loss associated with physical activity, an adjustment of carbohydrate intake, insulin and oral medications may be required before and after activity. The Canadian Diabetes Association recommends a gradual increase in the intensity, duration and frequency of physical activity over a period of weeks or months on an individual basis.

Hypoglycemia

It is essential that people with diabetes taking insulin and/or oral medications carry with them a source of fast-acting carbohydrate. The Canadian Diabetes Association recommends that 15 g of carbohydrate be administered for the treatment of mild or moderate hypoglycemia.

Examples of 15 g of carbohydrate for the treatment of mild to moderate hypoglycemia:

  • 15 mL (3 teaspoons) or 3 packets of table sugar dissolved in water
  • 175 mL (3/4 cup) of juice or regular soft drink
  • 6 Life Savers (1=2.5 g of carbohydrate)
  • 15 mL (1 tablespoon) of honey
  • 15 g of glucose in the form of glucose tablets

The recommendations indicate that glucose tablets or sucrose in solution is preferred because other sources of carbohydrate such as orange juice and glucose gels are slower to raise blood glucose levels.

For additional information on the management of hypoglycemia please see The Canadian Diabetes Association 2013 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada.

References