Here's some interesting data on restaurants per capita in different states. I'd imagine that in Utah you have two big issues. One is a large number of children, which is bound to depress per capita restaurants, and the other is weak sales of alcoholic beverages. A typical full-service restaurant business model is to count on drinks to provide the profit margin, so a Mormon-heavy state is going to have a weak outlook.
On the high end, the case of Maine is very interesting. Maine is a very popular vacation destination (I'll be going later this summer), so it often has a quantity of businesses that's out of proportion to its number of residents, simply because lots of people go there without necessarily living there.