No fanatical elite attitude here. My reasonable 100 miles includes coffee, citrus, bananas, rice, and all those other food and spice 'essentials' that makes international trade so much fun. But if I can source my food within Southern Ontario, then I will.
I've outlined my core foodshed above. I deliberately stretched north so I could claim wild blueberries were local for me. I still might have to wiggle my border into Quebec so I have access to their excellent cheeses.
The original 100 Mile Diet was created in Vancouver, Canada (that's the 160 Kilometer Diet when translated for real Canadians). I've always tried to have a edible garden, use pick-your-own farms, and make preserves when local produce was in season, so this idea appeals to me.