High Fructose Corn Syrup is in almost all processed foods with few exceptions including many condiments. It would be as difficult for restaurants to avoid products with HFC as it is most Americans who consume processed foods daily whether in fast food or at home.
If you go to non-chain restaurants that cook using the freshiest ingredients and make everything from scratch, you are more likely to avoid HFC.
If its a chain like Marie-Callendars or Perkins, I'd bet that its in all their bakery products, in their syrups, and in many of their meals, especially anything using a barbecue or terriyaki sauce.
I think it would be easier to avoid HFC in an individuals diet by reading labels and having it removed from products in home kitchens.
The HFC producers put advertisements on television telling us that HFC is fine in moderation, but fail to mention that its practically impossible to consume it in moderation since its in almost everything processsed especially bakery items (including many breads), condiments (including salad dressings, ketchup, pickles and even some mustards), yogurts, many beverages.
Its even in products that never had sugar in the past. Its often there because Americans like sweet tasting things so food processors up the sweetness with HFC to increase sales, not because the product needs it.
As HFC's were added to foods more and more starting in the 70's, we got more and more used to that super sweet taste. Now its a habit.
Drinking diet drinks with artificial sweetners don't really help either because it perpetuates our desire for sweet in our foods and beverages although in decades past we didn't eat as many sweet things.
Best way to avoid HFC is to eat mostly fresh or frozen fruit & vegetables rather than processed meals. Avoid condiments with HFC by reading the label or making your own. People used to know how to make simple salad dressings in minutes.
For a sweet tasting dessert beyond fruit, make it yourself from scratch or read the label on the box you're buying. You'd be surprised at how many salty snacks have HFC.