Given how much energy it takes to produce food, it’s better to drive than to walk.
Truth: The average diet has an embodied energy of 6kWh of fossil fuel per kWh eaten. The energy use of a typical car is 80 Kwh per 100 km. Walking uses a net energy of 3.6kWh per 100 km, 22 times less than driving. This means that if you have a typical diet, the carbon footprint of the food required to walk 100 km is 21.6kWh - still significantly less than that used by a typical car to travel the same distance.