Arguably every scene in the rom-com classic “When Harry Met Sally” is famous, but there’s one that truly resonates with restaurant owners and managers. Early in the film, at a roadside diner, Sally orders a chef salad and apple pie a la mode with a variety of menu substitutions: dressing on the side, ice cream on the side, heated pie and only real whipped cream, to name a few.

Picky customers come with any restaurant territory, albeit not always as demanding as Sally. We recently took a look at order data from April 2014 to March 2015 to better understand where the finicky diners are, how their special requests vary and what menu items are most often modified. Here’s a peek at what we found:

Picky Eaters Are a Diverse Bunch

On average, 28 percent of Grubhub orders include menu item notes: special instructions customers leave for certain food items. Geographically speaking, fickle diners are dispersed across the U.S., as illustrated by the top five cities for menu item notes:

1. Philadelphia
2. Baltimore
3. Dallas
4. New York
5. Boston/Houston (tie)

Customers aren’t uniform in the types of instructions they leave, either. 28 percent of menu item notes call for adding an ingredient not originally included in a dish, or an extra helping of one ingredient. 24 percent of notes request a certain ingredient to be removed. Only 6 percent of notes ask for items to be left on the side.

Top Five Health-Focused Requests

1. Sauce on the side
2. Dressing on the side
3. Easy on the cheese/no cheese
4. Easy on the mayo/no mayo
5. Substitute brown rice

In the last few years, consumer packaged good brands and restaurants have heeded customers’ call for more whole grains, natural ingredients and all preparations of kale. When it comes to ordering out, customers still opt for health-conscious menu substitutions. Restaurants should be diligent about keeping ingredient alternatives and the right packaging on hand – not to mention training kitchen staff – in order to appease any preference.

The Most Modified Menu Items

1. Turkey sub
2. Italian hoagie
3. Cheesesteak
4. Cobb salad
5. Hamburger
6. Chopped salad
7. Bacon burger
8. Turkey club
9. Cheeseburger
10. Taco salad

Customers tend to change up dishes that naturally include a lot of ingredients. The more toppings or condiments included in a given sub or salad, the more likely one will be swapped out. Offering build-your-own options for these types of dishes is just one way to placate picky eaters and avoid wasting product.

The Most Removed Ingredients

1. Onions
2. Tomatoes
3. Cheese
4. Mushrooms
5. Lettuce
6. Vegetables
7. Mayo
8. Sour cream
9. Olives
10. Beans

Case in point: common sandwich and salad toppings are the most frequently eliminated from pickup and delivery orders. Restaurants that enforce strict “no menu substitutions” policies, or charge extra to do so, may want to reevaluate their strategy and determine the cost-benefit of accommodating these requests.

Altering food for picky eaters is an inevitable part of restaurant customer service. Understanding your customers’ choosy habits can strengthen diner loyalty in the short term and eventually improve your bottom line, too.

Ready to tap into millions of new diners and grow your restaurant’s takeout and delivery business? Sign up with Grubhub for Restaurants today!