These workers hit the corporate account hardest

If you're wondering who is milking the corporate dinner tab the most, look no further than the world of high finance.

Four of the top five industries ranked by food order volume are in finance, according to an analysis of a year's worth of data from GrubHub Seamless.

Kristian sekulic | iStock / 360 | Getty Images

Investment banking took the top slot, followed by hedge funds, law, private equity/venture capital and asset managers.

Read MoreBest and worst tippers of food-delivery workers

"Looking at this list, these are industries notorious for their long work days," said Abby Hunt, GrubHub's director of public relations, during a phone interview. "It comes as no surprise that the ones with the long work days are going to be the ones to have their employees ordering more."

Employees show some serious java junkie behavior while on the clock. People place 110 percent more cappuccino orders while at work than while at home, 74 percent more coffee orders, 70 percent more iced coffee orders and 67 percent more latte orders, based on orders placed in the month ending July 14.

Read MoreFast food jobs pay $20 here... voluntarily

As the hours tick on, this over-representation of coffee increases. Employees burning the midnight oil from 10 p.m. to 2 a.m. are 500 percent more likely to order coffee while still at work than those at home.

While at work, employees tend to shun ethnic dishes to avoid messy eating and perhaps offending neighboring cubicles with pungent fare, Hunt said. Indian, Italian, Chinese, Thai and Middle Eastern dishes are all more commonly ordered at home.

"More people are working and eating at their desks these days so to have something that they can work while eating will help them improve their efficiency," she added.

Instead, they tend to gravitate more often toward salads, which comprise nearly one out of eight work orders.

This is a reflection of both a greater interest in nutrition at home and of the larger portion of work orders that occur during lunchtime.

"I think when people are at work they're perceiving food as fuel—not like at home where they would allow more indulgence," Hunt said.

—By CNBC's Katie Little