Revision of Canada's Food Guide
Development of Food Intake Patterns

Background

The work to inform the revision included modelling of food intake patterns. Modelling tested combinations of types and amounts of food until a pattern was found that:

• Meets the nutrient requirements of most Canadians, and
• Contributes to a reduced risk of chronic disease.

Dietary Reference Intakes nutrient standards and assessment methods were used for modelling.

Methods

A two step process was employed to model food intake patterns. Step one involved the creation of "composite" foods.  Each composite food represented a modelling group or sub-group. For example, the composite "fruit" was used to represent one choice of any fruit. The amounts of these groups and subgroups were manipulated until a satisfactory pattern was found. Composites were used to simplify the process of testing different amounts of food groups relative to nutrient standards.

Step two involved testing the pattern created in step one to allow for assessment using DRI assessment methods. Using the pattern from step one, 500 simulated diets were created for each age and gender group using individual foods. For example, if the food intake pattern created in step one recommended three servings of fruit, four simulated diets may include the following combinations: 1 apple, 1 banana, 1 pear; 1 plum, 1 orange, 1 banana; 3 apples; 1 apple, 2 bananas.

Both steps of the modelling were based on Canadian data.

• Step one used Statistics Canada's 2001 Food Expenditure Survey (FoodEx) data.
• Step two drew on food choices documented in the four most recent provincial food and nutrition surveys (British Columbia, Manitoba, and Ontario surveys for adult data; and the Quebec youth survey for children's data).
• An adapted version of the 1997 Canadian Nutrient File (CNF) reflecting the mandatory addition of folic acid to flour and enriched pasta was used as the source of nutrient values for the nutrient content of foods.

The simulated diets were evaluated to see if nutrient requirements were met. When evaluation of simulated diets yielded less than satisfactory results, modelling returned to step one to find a better pattern to test. More than fifty patterns were assessed before a satisfactory pattern was achieved.

Nutrient distributions of simulated diets were assessed relative to the appropriate Dietary Reference Intakes (DRI) values using recommended methodologies.

• For vitamins and minerals with an Estimated Average Requirement (EAR), the aim was to have 10% or less of all simulated diets with a nutrient content below the EAR. Nutrients assessed with an EAR include: folate, iron, magnesium, niacin, phosphorus, riboflavin, thiamin, Vitamin A, Vitamin B6, Vitamin B12, Vitamin C, and zinc.
• For nutrients with an Adequate Intake (AI), the median nutrient content of simulated diets was compared to the AI. Nutrients assessed with an AI include: calcium, linoleic acid, alpha-linolenic acid, potassium, sodium, fibre, and Vitamin D.
• The majority (at least 80%) of simulated diets should have carbohydrate, fat, and protein content within the Acceptable Macronutrient Distribution Ranges (AMDRs).
• Saturated fat and dietary cholesterol content of simulated diets should be as low as possible. Benchmarks of 10% or less of calories from saturated fat and 300mg or less of cholesterol were used.
• Median energy content of simulated diets should be at or below the median sedentary Estimated Energy Requirements (EER). EERs were calculated for each age and sex based on median height, weight derived from median normal BMI, and using a sedentary level of activity. A sedentary level of activity was considered most appropriate so that there was no overestimation of requirements.

In addition to the modelling, a summary of reported associations between foods and chronic diseases was done based on findings from two large reports: The WHO/FAO Joint Report on Diet, Nutrition and the Prevention of Chronic Diseases (2003) and the 2005 Dietary Guidelines Advisory Committee Report (USA). From this work, the association between specific foods with chronic diseases was examined. Foods that were assessed included: whole grains, vegetables and fruit, red and processed meats, legumes, nuts, eggs, vegetables oils, fish, energy-dense foods, sweetened beverages, milk products, and salt-preserved foods. These foods were assessed in relation to the risk of some chronic diseases such as overweight/obesity, diabetes, cardiovascular disease, cancer and osteoporosis. This work provided additional information for the development of guidance on specific foods.

Results

As a result of the modelling and review of reported associations between foods and chronic diseases, food intake patterns yielding satisfactory results for 16 age and gender groups were developed and are shown below.

Food Intake Pattern for Revised Food Guide

Number of Food Group Servings - Males

	2-3 y	4-8 y	9-13 y	14-18 y	19-30 y	31-50 y	51-70 y	71+ y
Vegetables & Fruit	4	5	6	8	10	8	7	7
Grain Products	3	4	6	7	8	8	7	7
Milk & Alternatives	2	2	3-4	3-4	2	2	3	3
Meat & Alternatives	1	1	2	3	3	3	3	3
Unsaturated fat (g)	30	30	30	45	45	45	45	45

Number of Food Group Servings - Females

	2-3 y	4-8 y	9-13 y	14-18 y	19-30 y	31-50 y	51-70 y	71+ y
Vegetables & Fruit	4	5	6	7	8	7	7	7
Grain Products	3	4	6	6	7	6	6	6
Milk & Alternatives	2	2	3-4	3-4	2	2	3	3
Meat & Alternatives	1	1	1	2	2	2	2	2
Unsaturated fat (g)	30	30	30	30	30	30	30	30

In addition, the following statements were developed to provide guidance on the types of foods to choose. These statements reflect the types of foods used in modelling to achieve acceptable results and are consistent with findings from the review of reported associations between foods and chronic diseases.

• Eat at least one dark green and one orange vegetable each day.
• Choose vegetables and fruit prepared with little or no added fat, sugar or salt.
• Have vegetables and fruit more often than juice.
• Make at least half of your grain products whole grain each day.
• Choose grain products that are lower in fat, sugar or salt.
• Drink skim, 1%, or 2% milk each day.
• Select lower fat milk alternatives.
• Have meat alternatives such as beans, lentils and tofu often.
• Eat at least two Food Guide Servings of fish each week.
• Select lean meat and alternatives prepared with little or no added fat or salt.
• Include a small amount - 30 to 45 mL (2 to 3 Tbsp) of unsaturated fat each day.

Simulated diets that followed these food intake patterns (including the statements) yielded satisfactory results across all nutrients and macronutrients examined. In particular, for nutrients with an EAR, the prevalence of inadequate nutrient content in simulated diets based on the final food intake patterns was less than ten percent. The median nutrient content of these simulated diets approximately meets the AI for calcium, alpha-linolenic acid and Vitamin D (except for those older than 50 years). Nutrients for which less than perfect results were accepted after discussion with experts and advisors include: linoleic acid, potassium, fibre (particularly for children), Vitamin D for those older than 50 years, and sodium. The assessment of simulated diets relative to macronutrients and energy content yielded satisfactory results.

The summary of the evidence around foods and risk of chronic disease provided additional information for the development of guidance on certain foods, specifically around whole grains, vegetables and fruit, and fish. The summary of this evidence was also found to be consistent and supportive of the overall food intake pattern derived from modeling.

Conclusions

This innovative evidence-based approach builds on assessment methods recommended through Dietary Reference Intakes reports. The strength of this approach is the ability to assess probability of nutrient inadequacy if the food intake pattern is followed. The food intake pattern developed through this method achieves satisfactory results across most nutrients assessed and is consistent with evidence linking diet to reduced risk of chronic diseases. This approach provides rationale for specific messaging on whole grains, orange vegetables, dark green vegetables, fluid milk, unsaturated oils and fat, fish, and lower-fat choices across food groups. Any person following the food intake pattern has a high probability of meeting their nutrient requirements as well as a low probability of nutrient excess. Furthermore following this pattern and specific guidance contributes to reduced risk of chronic disease development.