The purpose of dietary guidelines is to promote a pattern of eating that will allow Canadians to both meet their nutrient needs and reduce their risk of developing chronic disease. Canada's dietary guidelines includes both scientific components (Dietary Reference Intakes) and food guidance for consumers (Canada's Food Guide).
Dietary guidelines in Canada are based on updated nutrient requirement values and a new focus on the relationships between nutrition and health. The Dietary Reference Intakes (DRIs), established by Canadian and American scientists through a review process overseen by the US Institute of Medicine in collaboration with Health Canada, reflect the current state of scientific knowledge, and were used to update dietary guidance in Canada.
Dietary Reference Intakes
The Dietary Reference Intakes (DRIs) reflect the current state of scientific knowledge with respect to nutrient requirements to prevent deficiencies as well as lowering the risk of chronic disease. They replace the previously published Recommended Nutrient Intakes (RNIs). The DRIs are a comprehensive set of nutrient reference values for healthy populations that can be used for assessing and planning diets. Unlike the previous RNIs, the new DRIs present multiple values for each nutrient, instead of the former single value approach. These different categories of reference values results in a greater range of tools with which to assess and plan diets.
The DRIs were developed by both Canadian and American scientists through a review process overseen by the US Institute of Medicine in collaboration with Health Canada. They make use of the concepts of probability and risk to assess the risks of inadequate and excess consumption of each nutrient. Where adequate information is available, each nutrient has a set of DRIs.
To reduce the risk of nutrient inadequacy, each nutrient has either an Estimated Average Requirement (EAR) and a Recommended Dietary Allowance (RDA), or an Adequate Intake (AI) --an AI is set for a nutrient when there are insufficient data to determine an EAR and RDA. In addition, many nutrients have a Tolerable Upper Intake Level (UL) -- the highest average daily nutrient intake level that is likely to pose no risk of adverse health effects.
The macronutrients also have Acceptable Macronutrient Distribution Ranges (AMDR) -- a range of intakes (represented as percent of energy intake) that is associated with reduced risk of chronic disease while providing adequate intakes of essential nutrients.
Carbohydrates and Sugars
Total Carbohydrate: The AMDR for carbohydrate is 45-65% of energy intake for all adults and children. This range is "based on evidence indicating a risk for coronary heart disease (CHD) at low intakes of fat and high intakes of carbohydrate and based on evidence for increased risk for obesity and its complications, including CHD, with high intakes of fat."
The RDA for carbohydrate is 130 g/day for adults and children "based on the average minimum amount of glucose utilized by the brain. This level of intake, however, is typically exceeded to meet energy needs while consuming acceptable intake levels of fat and protein." Median intakes are 200-330 g/day for men and 180-230 g/day for women.
Sugars: The conclusion of the report was that, "based on the data available on dental caries, behaviour, cancer, risk of obesity and risk of hyperlipidemia, there is insufficient evidence to set a UL for total or added sugars." Although no UL was set for added or total sugars, "a maximal intake level of 25 percent or less of energy from added sugars" was suggested for adults and children "based on the decreased intake of some micronutrients of American subpopulations exceeding this level." However, this level of intake far exceeds current average intakes, which are estimated to be 15.8 percent of total energy intake (calories) in the U.S. and 10-13% of energy intake in Canada.
Canada's Food Guide
Eating Well with Canada's Food Guide suggests an eating framework for Canadians over the age of 2. The rainbow design depicts the four food groups (Fruits and Vegetables, Grain Products, Milk and Alternatives, and Meat and Alternatives) in proportion to the suggested servings from each group. The Food Guide recommends how many Food Guide servings Canadians should try to eat each day, based on age and gender. Individuals are encouraged to eat a variety of foods from the four food groups and to include a specific amount and type of added oils and fats. This pattern of eating has been developed to meet nutrient standards (Dietary Reference Intakes) and to be consistent with evidence linking diet to reduced risk of obesity and chronic diseases such as type 2 diabetes, heart disease, osteoporosis, and certain types of cancer.
Canada's Food Guide is designed to support the achievement and maintenance of a healthy body weight in sedentary Canadians. Specifically, this guide meets the energy and nutrient needs of sedentary, normal weight (Body Mass index of 18.5-24.9) Canadians. The Canadian Community Health Survey of leisure-time physical activity from Statistics Canada indicates that approximately 50% of the population, aged 12 and older, meet this sedentary criteria. The other half of Canadians who are considered active are advised to choose extra Food Guide Servings from the four food groups.
The previous Food Guide recognized foods that did not fit into the four food groups by creating a category called "Other foods". This group included a wide range of dietary items and beverages that contribute to taste and enjoyment in eating. The inclusion of these foods in the Food Guide is in keeping with the healthy eating philosophy that all foods can be part of a healthy eating pattern. Because of the change in mandate of the new guide to achieve and maintain a healthy body weight, a "directional statement" to "limit foods and beverages high in calories, fat, sugar, or salt (sodium)" is included in the place of the "other" food category.
Sugars in the Food Guide
Sugars occur naturally in a variety of foods in the four food groups. Sugars are also added to these foods in a variety of forms for different functional purposes, including sensory, physical, microbial and chemical (See Functional Properties of Sugar). Naturally occurring and added sugars are consumed as part of many foods in the four food groups, such as breakfast cereals, yogurt, and tomato sauce.
The current version of Canada's Food Guide encourages Canadians to limit foods and beverages high in calories, fat, sugar, and salt. However, it is important to note that "limiting" these foods does not equate to avoiding them altogether. Many of the foods that fit into the four food groups are made more enjoyable by adding small amounts of sugar. Without sugar, many individuals may not consume healthy foods that contribute to their nutrient needs. For example, without sugar, many breakfast cereals providing essential nutrients, would be inedible.
Canada's Food Guide suggests eating foods lower in sugar to help limit extra calories in the diet. However, The Dietary Reference Intakes for Macronutrients report states "a negative correlation between total added sugars intake and body mass index (BMI) has been consistently reported for children and adults". In addition, active Canadians can consume foods that are higher in sugar and/or calories to meet energy demands. A number of foods and beverages, such as lower fat cereal and bakery products and beverages such as fruit and sport drinks can provide the additional calories and carbohydrate that they require.
Dietary Guidance References
Canada's Food Guide, Health Canada, 2007
Dietary Guidelines - Preparation and use of food-based dietary guidelines, FAO
Dietary Reference Intakes, Health Canada, 2013
Dietary Reference Intakes for Macronutrients, Institute of Medicine, 2005
Dietary Reference Intakes for Sugars, Canadian Sugar Institute, 2004
Estimated Intakes of Added Sugars in Canada and Relationship to Trends in Body Weight. Canadian Sugar Institute, 2011