Living in London all my life, we grew up in a car-less household and my dad would do nearly all of the food shopping for our family of 6 himself (7 for a while when my uncle lived with us while he was studying), carrying it all home on the bus. I am still car-free and can get my shopping home using the bus or my bike on the way home from work. If you can't do that in your city, then that's the fault of your city's planners. It's a failure of providing good public transport.