poor diet
two issues:
1. Poor diet choices in my humble opinion. To begin with, in the states, most fresh foods used to be canned. The long distances makes it costly to ship fresh produce. These days people from the US are much more interested in farm to market produce. However, this is not pervasive, nor the norm. Besides which, the new fresh grocer approach is too expensive for most. Remember, people in the US are conditioned to buy by value and by the month, as opposed to by quality and every other day or so. Even organized organic GM free foods are expenisve (take Whole foods, popularly known as Whole Pay Cheque)
Another issue is the dichotomy between affluent and 'underclass'. I lived in Philadelphia, Pa. for almost a decade. I always found it ridiculous that certain sections of that city are completely void of markets selling produce and healthy food. Instead there is the petrol station, fast food, or the 'corner store' with their pale sized soft drinks and junk food.
2nd is consumerism. The telly advertises crap food and so the people buy crap food.