This is only peripherally related to the blog, but I found this entry on the New York Times' "Well" blog really interesting.

To sum it up, a University of Washington study found that high-calorie foods (like candy, pastries, breads and snacks) cost an average of $1.76 per 1,000 kcal, while low-calorie but nutrient-rich foods (like fruits and vegetables) cost $18.16 per 1,000 kcal. That's a big difference!