“The 4,500 people of Musselshell County, Mont., collectively buy the least healthful groceries of any county in the United States. Their baskets are loaded with fat and sugar, Nielsen data show. They aren’t big on fiber or protein.” WaPo’s Caitlin Dewey on a new study that attempts to explain why eating habits are so bad in Musselshell (and counties like it). It turns out it’s not just about access to healthy food.