I am originally from Portsmouth, OH (bottom center of the state, along the Ohio River) on Rt. 52 (Cincinnati and points west, and Huntington, WVa and points east) or Rt. 23 (Columbus and points north), and though I've lived in three major east coast cities, there are two food places for which I've never found equals...
If you're traveling anywhere near the area, I strongly encourage you to stop at:
Hamburger Inn (1547 Gallia Street, 740-353-9248) - this tiny hole in the wall has been around since the 20s, and serves the most amazing small burgers you will ever find - cooked in oil on a grill installed in the 30s (after the original was destroyed in a flood), the burgers are moist and perfectly cooked (if you order a cheeseburger, the cheese is placed on top of the burger and a little oil flipped onto it), placed on a soft bun, sprinkled with a little salt and topped with pickles (other condiments available). I also highly recommend a side of their chili or bean soup. You'll have to take a break from watching your diet, but you won't regret it!
Down the street, you will find the best doughnuts in the entire world:
Mrs. Renison's Crispie Creme Donut Shop (not related to the other major doughnut maker) (1202 Gallia Street, 740-353-5890) - this shop has been in business for what seems like forever and makes the best doughnuts I have ever tried - all varieties are outstanding, but be sure to try the glazed Crispie Creme original and the "Mountain Top" (chocolate yeast doughnuts with chocolate icing and a center puff of white creme). The doughnuts are always light and nearly greaseless, and the glazes melt almost instantaneously. Open 24 hours, they make fresh batches throughout the day (I know for sure around 10pm, but call ahead for the best time to get them warm). These doughnuts are so good, that I can't bring myself to eat any other kind - you really need to try them!!