There's a few stores listed in Calgary - this is what I pulled off the site:

Community Natural Foods 403-229-2383
1304 10th Ave SW
Description: A large store, featuring bulk soy powder and soy flour,bulk nuts, tons of packaged protein powders, vitamins, pottasium pills, soy pastas

Lewis Chocolates
2 locations apparently but the one I know about is in Bankers Hall, 2nd floor beside Reiko's sushi
Description: Delicious sugar-free chocolates made with maltitol...my favourite is the chocolate cashew toffee one and the haystack (chocolate coconut) and the almond bark is lovely too. Others are chocolate mint, chocolate lemon cream, various nut chocolates, etc.

Morning Sun Health Food - North Hill
Description: Whole psyllium husk Now brand stevia soya pro powder (protein isolate) Bobs Red Mill soy flour (there were 4 or 5 Bobs products) They had soy nuts 3 flavours, but I didn't find them low in carb so I didn't buy any. They also had bars and Atkins shakes, that sort of thing. They are a chain (all over Calgary, one in Airdrie one in Sherwood Park), but I wasn't able to find out if all stores carried these things.

SUPPLEMENTS EH! 403-225-8942
202 12101 Lake Fraser Dr.(Avenida Mall Area)
Description: Low Carb Products for Atkins, The Zone, Body For Life, and many more, including supplements for low carb diets.

Hope this helps! I'm thinking that I'll visit the two stores that sell Atkins products at least (although I'd sure like to find the Lewis chocolates!).

Lynne