According to Stuart Rose of Marks & Spencer in the UK "People's purses are being squeezed," he said. "A seismic shift [in shopping habits] is going on."
He blames very poor performance of M&S on not only economic factors but specifically fuel prices and that people are shopping locally rather than at out-of-town shopping centres to avoid using gas.
I am not sure how this will net out but we should expect to see a shift in trip types driven by a myriad of factors - including fuel prices.
Although I am not sure of the impact in Canada of fuel prices on shopping habits. The average distance driven for a stock up trip is 7km in total. That would cost about $3 in gas - an increase from $2 prior to the increase in prices. I am not sure if people are that sensitive to gas prices - unless of course the motivation is emotional and the simple act of driving causes pain.