Following the positive results from a small bowel biopsy, a Celiac diagnosed person should begin a gluten free diet for life. In Canada, this would mean consuming foods that do not have the ingredients of wheat, rye, barley, oats, and triticale. Yes, this means No Beer, Pizza, donuts, or cookies. This is fairly easy to do, once you are familiar with gluten free products and their ingredients. You will also find ways to make these foods using ingredients of rice, potato, corn, and tapioca.
Different countries have different variations of the diet.
Those in the USA do not eat vinegar, for example, and some countries have no problem with oats in the GF diet. When dining out, you should always be aware of cross contamination. The first place to go to for support is the Canadian Celiac Association. They have Chapters in Provinces all across Canada. More info here .