Where can I access the recommended dietary allowances by age group? Canada's Food Guide is a good place to see the recommended number of servings of each food group by age.
I'd like information about healthy vegetarian diets. The Dietitians of Canada have very informative information on Vegetarian Diets.
What is the glycemic index? Diabetes Canada has a very good explanation.
I have a list of foods and I'd like to know which nutrients each food item contains. Try the Canadian Nutrient File. You can download a booklet that contains information on the most popular foods or search the database.
How can I achieve a gluten-free diet? Take a look at this Gluten-Free Eating guide from the Canadian Celiac Association, Dieticians of Canada and The Global Resource for Nutrition Practice.
What size is a daily serving? Again, Canada's Food Guide is a good place to see serving sizes.