Delivery for 2: What people order on Valentine's

Valentine's Day. Singles Awareness Day—call it what you want, but come Saturday, one thing is for sure: many people mark the day with food.

GrubHub crunched its data from last year and found a noticeable change in what diners order alone, and what pairs of diners order for takeout and delivery, compared to what's ordered on other days of the year.

Overall, sushi proved to be a big hit in Valentine's Day orders. Of the dishes that were more popular than the rest of the year, half of the top 10 were sushi items, said Allie Mack, senior associate of public relations at GrubHub, in a phone interview.

"If you're thinking about couples in general, I think sushi is one of the sexier foods," Mack said. "It's easy to eat with chopsticks. It's not something that will get caught in your teeth unless you're getting one of those massive rolls."

Couples ordered more sashimi, sushi and several Italian dishes than on the other days of the year, possibly because Italian is also considered a romantic cuisine.

Which items do people steer clear of during the holiday? Nothing says "I'll wait until after Valentine's to order that" than bread sticks with cheese. People are 85 percent less likely to place it in the GrubHub cart then than on a typical day.

Read MoreBottomless burgers in 2015? Look here!

Solo diners gravitated to many cuisines traditionally seen as heartier ones.

"I don't want to assume too much causation or add the why, but it's clearly heavier, more comfort foods that people are ordering," she said.

Read MoreHow to police your spouse's spending

Indeed people ordering by themselves were 277 percent more likely to order from restaurants that identified themselves as pizza ones and 276 percent more likely to order from wing restaurants than throughout the year. Late night, Italian and pasta dishes were more than three times more common. The top three dishes that single orderers more commonly ordered on Valentine's Day than couples were yellowtail, tossed salad and chicken alfredo.

College being in session and Valentine's Day landing on a Friday last year might have helped fuel these trends since college diners skew results and people's dining patterns could change on the weekend, Mack said.

As for dessert, cheesecake took the cake.