There are plenty of people who consume highly processed foods and stay skinny. There are plenty of people who eat greasy, sugary, fattening foods who stay skinny. The problem is not car culture, sugar, and processed foods. The problem is overeating. America, and the rest of the first world has major issues with food addiction and a culture associated with "eating until the plate is clean"
We've had a food surplus for a long time, why is obesity a relatively recent problem?