As Uber gets ready for its 2019 public market debut, it wants to be known for more than just ridesharing.

Its businesses now cover everything from flying cars to patient pickups and electric scooters. But it's the company's food delivery service, UberEats, that is seeing the strongest growth.

UberEats is already the fastest growing meal-delivery service in the US, according to a Business Insider research report. On Tuesday, the unit, which operates like its own startup inside the larger company, announced that it wants to be available to 70 percent of the population by the end of this year, up from 50 percent currently.

In emailed comments to CNBC, Uber CEO Dara Khosrowshahi said that food delivery was one of the company's first big bets.

"We wanted to use the power of our network and technology to move beyond ridesharing," Khosrowshahi said.

Khosrowshahi said it ultimately drives growth back to the ridesharing platform. In 2018, 40 percent of new Uber Eats users were new to Uber.

For example, Uber is not available in Vancouver, Canada, but Uber Eats is. Janelle Sallenave, Head of Uber Eats North America, told CNBC that food delivery gives first time customers a chance to be exposed to Uber.

The company is quick to point out its success in Uber Eats. But, as it looks to tap public markets, it could have more difficulty convincing investors that its other big bets, like autonomous driving and flying taxis, will pay off.

Khosrowshahi said the vision is broader.

"As our businesses continue to grow, we see Uber's platform becoming the Amazon of transportation and movement," he said. "Uber Freight is transforming the trucking industry by enabling carriers and drivers to push a button and book a load at an upfront price. Adding JUMP electric bikes and scooters in our app has given commuters a new option and made it even easier to live without a car. And Eats is fundamentally changing how people experience food."

But some analysts say that the other businesses could make it more difficult to value the company in an IPO.

Kathleen Smith, principal at IPO research firm Renaissance Capital, says it's better to be a pure play in ridesharing, like Uber's smaller rival Lyft.

"Lyft is totally focused on ridesharing," she said. "All [Uber's] businesses are startup businesses."

Bankers reportedly think all of Uber's pieces could be worth $120 billion in the public market, a stretch from its most recent funding round, which valued the company at $76 billion.

Khosrowshahi said Uber "suffers from having too much opportunity as a company." And when asked which businesses profit will come from, Khosrowshahi responded, "All of them, hopefully!"

Whether investors believe in this narrative is another question — and it will be reflected in Uber's ultimate valuation.