Maybe food is more expensive in Canada, but my family of 4 never eats out and we spend $250-275/week. I cook most things from scratch and I buy mostly local or organic dairy and produce which costs me an extra 25-30% depending on the season.
We buy fruits and veggies in the specialized "market" stores. Supermarket prices are double. We buy stuff that's on sale (pretty much everything goes through a cycle of sales or is on sale somewhere). We shop for dairy across the border where organic milk costs about half...
(Vancouver, BC, area)