You misinterpreted the data, as I did too when I first heard of the study last year. According to the report you source, the annual cost of avoidable food loss and waste in Canada is $1,766 per household, NOT what the average Canadian household spends. According to the research, the household spending portion represents around 21%. The rest is waste during production, manufacturing, processing and distribution. Further, some of the food loss is unavoidable, such as when inedible food by-products, like animal bones, are discarded.
That said, the study appears well researched and the main takeaway was that up to a third of the food waste generated could be avoided thru better food production management and go a long way towards both feeding the world and mitigating the environmental consequence of food waste.